When writing creatives at home, i use a theasurus, because there are so many similar words that can be used in the same context, but each will make their own tone and effect, so i like to look at all the options and select the best one.
Then, to remember and be able to use this word later in my vocabulary, I use memory techniques to try and remember it.
for example: think of a route that walk by almost everyday, and you know it really well. For example, you can remember where the garbage bin is when you walk by.
then, find your word that you want to remember, and think of a ridiculous image that comes to your mind when you think of it, and its meaning. For example: abhor - i think of a boar with abs, that is really angry and disgusted (the meaning of abhor is to regard with with disgust).
then assign this image onto your walk, so that whenever you go through it in your head, or physically, you can think of it and remember the word and its meaning.
i hope that makes sense!
when you write essays though, i would not suggest using a thesaurus. It is obvious and looks bad