Can anyone check the correctness..?

"We have been playing last 1 and half month with our internal team"

"We have been playing last month and a half with our internal team" might still require clarification depending upon context. For instance it isn't clear whether you're playing in opposition to, or by means of, the internal team. When I presented it to my Better Half, who is much smarter than I, she suggested "…playing…with…" might instead mean either (1) reorganizing or (2) joshing, taunting, or ridiculing it

I am supposing we control two teams, one independent and the other internal to an organization, perhaps our own, playing a third team whose affiliation isn't apparent:

"Since our usual opponent, the independent team Irish Ruins, had recently lost several important members, for the past month and a half our own team, International Clipboard Corp's Griffity Grogs have been competing instead with newcomer Let's Killum All"

"Hope every one conscious about their own strength and weekness"

...which I'm sure Achu you'll agree might be defined as "Of or pertaining to a period of seven days." Of course s/b "weakness" tho usu more'n one:

"Hope everyone conscious about (of) their (his) own strengths and weaknesses"

"Now we are entering to next stage of our strategy" Presume typo...

"Now we are entering the next stage of our strategy." If we make the presumption that knowing his own strengths etc might make the participant better deal with a more complex or difficult next stage, then one might write:

"….weaknesses because now…."

"So I expect your 100% commitment in to our upcoming tournament which is going to start on Mar 01 to April 18"

"So I expect your 100% commitment to (in) our upcoming tournament which is going to start (March 1 and extend through April 18), (on a date as yet undecided but probably March 1 to about April 18), (March 1 and is expected to terminate on or before before April 18)

"The more details about the tournament will send you shortly."

First "the" unnecessary. Also (literally) details cannot send and it isn't clear, if they could, exactly where it is they send you

Forgive me Achu, couldn't resist

"More details about the tournament will be sent you shortly."
"Shortly we'll send more details about the tournament"
"More details about the tournament coming shortly"
"More details will be sent shortly"
"We'll send more details about the tournament shortly."

In any case Achu you can see how important the context if we're to be of any help at all


…Yet with my sincerest apologies, yea, mine is a compulsion. Achu you're to be congratulated for your determination to learn a very difficult language