Good points all, but i'm going to have a little fun with this.
First, the question implies that England set out to conquer "different countries," and that is simply not true. This is why i say the question is naïve and simplistic. I suspect that your teacher expects you to puke up whatever line of BS s/he has been "teaching," but that you have not been paying attention and now you come here in a panic looking for answers.
The simplest answer is venture capitalism. Without going into details, as a result of the Roman empire's policy of federation of "barbarian" tribes, a custom grew up that one would give one third of one's plunder to one's feudal lord (i won't go into a detailed explanation of that). So, if i'm the Duke of Earl, and i send you to France to fight for the King, you are to give me one third of all the plunder you take. When well managed, that was considerable. (However, when the French were acting intelligently, a rather rare circumstance, the English would get little or nothing after marching across France and reaching the coast hungry, shoeless and dropping from disease) This worked all down the line. The captain of a company or men at arms and archers got one third of whatever plunder those boys took. He, in his turn, handed over one third of his take to his liege lord. He would then hand over one third of his profits to the king. Everybody wins (except the French, who paid enormously for stupidity and hubris).
So, if i'm the Duke or Earl, and i send Bsie out with a company of my men at arms and archers, they will try to get all the plunder they can, and will give Bsie one third of what they take. Suppose they get 27000 pieces of gold. They will then give 9000 gold pieces to Bsie. Bsie then gives me 3000 gold pieces, and i give 1000 gold pieces to the King. That's the ideal, at any rate, and sometimes it worked, and sometimes nearly everybody was killed or maimed and the few survivors staggered into Bordeaux or Calais, just glad to get a hot meal and wait for the next ship back to England.
But this lead to a tradition of what can reasonably be called venture capitalism. Leaving aside the crusades, which everyone screwed up, the first attempt at overseas exploration and trade was by Prince Henry the Navigator of Portugal. His efforts were largely administrative--finding capital to underwrite the voyages, encouraging exploration and trade, and even putting his own money into the effort. He was fairly rich for reasons i won't go into here. From his efforts, the Portuguese would "conquer" islands in the Atlantic off the coast of Africa, which proved very useful to them long after Henry had died. Henry attempted to muscle his way into the Muslim slave trade on the west coast of Africa, and got his military ass handed back to him. That proved to be a good thing, as it lead the Portuguese to continue down the coast of Africa. Almost 30 years after Henry died, Dias reached the south coast of Africa, at what he called (in Portuguese), the Cape of Storms, we now call it the Cape of Good Hope. That was in 1588. In 1598, Vasco da Gama reached Calicut in India, where he failed to impress the local potentate. He started with four ships and 170 men. Half the men were lost in storms at sea or died of scurvy, and he lost two ships. However, When he returned in 1599, he got a hero's welcome, and he made King Manuel rich. The spices they brought back proved to be worth 60 times the entire cost of the expedition, even after the King paid everyone their contractual wages (he got a break on that since only half of them survived).
The Portuguese has been making good money on gold dust, irvory and the slave trade in West Africa even before da Gama's voyage, which may explain why Queen Isabella of Castille decided to "underwrite" Columbus. Don't believe all that old BS about Isabella hocking the crown jewels. She put the arm on a few rich nobles to pay for the crews and supplies, and she simply seized three ships from a merchant in Seville for Columbus to sail in. They were not very good ships, but seaman in the age of sail were pretty good at keeping their crappy ships afloat, and repairing them when they hit land. The story of Columbus is sordid and not germane here. Suffice it to say that Spain subsequently erected the larges empire in the world since the Romans. Their method was an expansion on the one third principle of classic European, feudal venture capitalism. They divided the plunder into five parts. One fifth went to the church, and you can bet there was a priest or friar in every expedition to keep an eye on the loot and the church's share--i mean, to see to the spiritual welfare of the conquistaores
and to convert the noble savages. Yeah, that's it, they were just there doing god's work. One fifth would go to the Crown, and a royal account went along on every expedition which had gotten royal approval. The leader of the expedition got one fifth, his offices got one fifth, and the majority, the soldiers and sailors, split the remaining fifth. The difference in the fortunes of Cortés and Pixarro is instructive. Cortés did not get approval up front, and was eventually impoverished by royal accountants and lawyers. Pizarro, despite being a bastard. illiterate and a former swineherd, either got good advice or naturally had a good head on his shoulders. He had all his ducks in a row, and took a friar and a royal accountant with him. Of course, he grew so rich that he attracted jealous rivals, and being the bastard son of an unimportant family, he had no powerful friends at his side when his palace in Lima was stormed, and he was murdered. Nevertheless, the Spaniards managed through that bastard child of feudalism, venture capitalism, to create a vast empire that spanned the globe and to import so much silver and gold that they ruined their own economy and to a lesser extent, the economies of the other European nations. (They were unable to say "runaway inflation.")
During most of the 15th century, when Henry the Navigator and the Portuguese were out looking for gold, ivory and slaves,the English were screwing around in France and losing the Hundred Years War. Then they went home and fought a series of civil wars called the Wars of the Roses. While the Bartolomeu Dias was sailing down the west coast of Africa, looking for the spot to turn the corner, Henry Tudor, now King Henry VII of England, was putting down the last gasp of the failed house of York, and establishing one of the most interesting dynasties in English history. The Dutch weren't doing much of anything unusual, just fishing the North Sea to feed Europe's Catholics during Lent, and thereby becoming some of the greatest sailors in Europe. (The North Sea ain't no Disney World--in fact, it has some of the worst storms and the roughest waters in the world--it made the English and the Dutch great sailors, though.)
Ninety years after da Gama landed in India, in 1588, The Spanish sent a great fleet, called the Armada, to accoplish destruction of the Dutch (who had rebelled against the Spanish several years earlier--we won't bg into why the Netherlands belonged to Spain); and to invade England. The Spanish were fairly well-equipped, and had the largest navy in the world at the time, with lots of experienced officers and crew and marines, and the expedition was well-organized and well supplied. The Dutch were basically an organized crime syndicate afloat, and had been gleefully making monkeys of the Spanish for a generation by then, and constantly raided the coast of the Netherlands for fun and profit--oh, and to win their independence . . . yeah, that was it, they were freedom fighters. The English were largely a pack of well-heeled pirates who had been raiding Spanish trade for a generation.
The Spanish should have won. They had everything going for them, while the English had no fleet organization and were so poorly organized that some of their sailors actually starved to death before they finally saw the Armada off. What happened to the Spanish was a mixture of King Philip II attepting to micromanage the enterprise in an age of slow and unreliable communications, and the arrogance of the Duke of Parma. The Duke of Medina-Sedonia, who commanded the Armada was supposed to sail past England and pick up Parma's army, thought to be about 30,000 men. Parma had only about 16,000 fit for service, but they were hard bastards, and would have made mincemeat of the English. Elizabeth had about 4000 troops, of dubious quality, but many were veterans of the wars between the Spanish and the Dutch. But Parma refused to cooperate. When the Armada sailed past England, the English nipped at their heels, but were unwilling to close with the Spanish, which was a good thing, because the Spanish would have overwhelmed them. After screwing around way too long, Medina-Sidonia agreed to sail to a port called Gravelines to pick up Parma's army, and the English, for all that they were poorly organized and had no coherent command, were still good enough sailors to see their advantage. They caught the Spanish on a lee shore, closed to within a hundred yards and blasted the sh*t out of them with cannon fire, something for which the Spanish were not prepared. Medina-Sidonia finally decided to sail away to save as much of his fleet as he could. Don't believe all that old BS they trot out about the Armada and Hearts of Oak--they got lucky in a situation in which they should have been doomed.
Elizabeth died in 1603 and King James (you know, the bible guy?) could not shake the dust of Scotland off his boots fast enough. It was King James I who initiated English venture capitalism of the colonial type. Jamestown was founded in 1607, even though the English had been calling North America "Virginia" (in honor of Elizabeth, a putative virgin) for two generations, and doing f*ck-all about it. Although the London Company which established Jamestown went bankrupt, the pattern was set. The Massachusetts Bay company, the Muscoy Company, The Hudson's Bay Company--these are all examples of venture capitalism in action in England. Some failed, and some succeeded. Often, the English were not actually dealing with other countries--not in the 19th century sense of nation states. What usually happened is that English merchants got established somewhere, cried and whined to the Crown, and the Royal Navy or redcoats were sent to haul their chestnutes out of the fire. Their one great colonizing venture, North America, fell apart because the Crown and the government were lousy at managing their people and their resources--hence the American revolution. When merchants, who already owned about half of Parliament, set up their trade routes, and the navy and the army were dispatched to rescue the merchants, often in some phony-baloney crisis, England more or less stumbled into empire.
So the simple answer is, it was venture capitalism.
I'm sure that this has been largely incomprehensible for you, and as it doesn't puke up whatever false historical pap your teacher has been feeding you, i suspect it will have been no help at all to you.