@osmith20,
I am going to suggest two books to you.
1) Stephen King's
On Writing
2) Ray Bradbury's
Zen in the Art of Writing
Both authors give a few important pieces of advice. Their advice is similar, but you might respond to one author more than another. That's why I am suggesting both. Here's what they suggest, mixed with my own experiences and ideas, and I am talking about fiction writing but you'll see in a moment that it's a lot like essay writing:
- Write about 2000 words per day as your goal. That's something like 5 pages single-spaced or 7, 7 1/2 with one and a half to double spacing. It depends on font size. For me, that takes anywhere from one to two hours.
- Write every day. I would add, though, that exercising the writing muscle can be done with non-creative writing. So that means blogging, essays, etc. saab's idea of a diary is excellent. But spend time writing.
- How do you do the first two? Set a calendar reminder and block off the time. Try to make a time when things are fairly quiet and you're not distracted by the siren song of social media. I personally like 2 - 4 PM or so for fiction writing, but if I have to work, I do put it off. Life intervenes and you have to make money; sobeit.
- Don't worry if your first draft is horrible. Everybody's is.
- Use writing prompts to get started. Just Google them.
- Don't like the writing prompts you're finding? Then consider your favorite TV show or film. Ask yourself: what happened before the film (or series) started? What happened after the credits rolled? What happened to a certain side character? Don't knock fanfiction (for that's what I am suggesting is); lots of people get started that way.
- Keep a writing jar filled with stream of consciousness ideas which don't have a home yet. Just park them in there, and withdraw from that bank (there's a mixed metaphor, eh?) when you've got writer's block.
- Outline if that suits you. Personally, I am an outliner/plotter, but a lot of people (King, for example), write by the seat of their pants and don't really know what's going to happen until it gets onto a page. There's nothing wrong with that although those folks tend to need more editing later.
- Read. A lot. Figure out how authors did something or other. How did they foreshadow? How did they make you keep turning the pages, and going from chapter to chapter? Did the mystery fall apart at the end? Did the ending satisfy you? Or not?
Now, to address essay writing directly. In high school, we were taught a four-step process.
1) Read the subject matter thoroughly and take notes. Research as necessary. Look up any words you don't know. Get your citation ducks lined up (if needed).
2) Outline what you are going to say. You got three points? Then they need to go in an order that makes some sense. Start with your strongest point first, and work your way down to the weakest one.
3) Write a first draft (kinda looks like what I wrote above, eh?). Never mind if it stinks; you're going to fix it in step 4.
4) Read over the draft and rearrange it if you need to. Consider the points you are making. Could you make them stronger? Did you write something convincing, or half-hearted? Would you be persuaded if you were reading this, and it wasn't your work? I have found reading aloud helps tremendously in this area. This step also means finishing your work, e. g. editing it and handing it in.
Put away the online generator; it's a form of cheating. The thesaurus is fine but if you are using it as a crutch then cut it out. I suspect it's more likely that you're using it as a procrastination tool. It looks like work, but it really isn't. Shades of meaning are important in your work, but that's what step #4 is all about. You seem to be using it for step #3. Don't.
I write for a living, both fiction and freelance blog and webpage writing. I have to get my writing engine going pretty much every single day. This is what has been working for me for years.
Best of luck to you.