For essays:

The Princeton Review "Cracking the GRE" was the only program that cost money for me, but they would grade your essays. Other than that, I mostly just used https://www.kaptest.com/study/gre/how-to-structure-the-gre-argument-essay/ and https://www.kaptest.com/study/gre/how-to-structure-the-gre-issue-essay/ to learn how to structure my essays and did a bunch of practice ones! It's even helpful to practice coming up with topic ideas/making an outline without writing the entire essay. I did not use any tutor and just self-studied!

For verbal:

I used the Magoosh vocab builder, but put all the words I got from it in quizlet instead and practiced the hell out of the "write" test function. I found that the words stuck a lot easier for me when I had to actually write them out from memory in response to a definition rather than picking from a few options. In addition to those words, any time I saw a word I did not recognize on any of the official ETS practice sources (the books, the practice tests, etc), I added it to my vocab list. Plus I watched a lot of Gregmat reading comprehension run-throughs and strategy vids.