Grammar and awkward sentences. I had instances where folks mentioned some of my phrases are confusing at times and why my prose suffers. I try to find a beta for that, otherwise I do extra work on editing and read my stuff aloud. That tends to work, though some awkward sentences still slip here and there.
One other thing is describing body language and inner emotions. I feel tend to repeat the same expressions and inner emotions so I need variety. Using The Thesaurus Dictionary has helped quite a bit on the emotions part, so I tend to have it in hand with me whenever I write/edit.
I feel like I'm missing a lot in terms of just. Comedy. I used to be better at it and I don't know what happened? I'm just not as quick on it anymore- I can usually find appropriate space for jokes given a few read-throughs but it just isn't coming as easily. Quite honestly I just need to start properly reading again. It always noticably improves my writing in all areas.
Actually writing! I'd do something like write 5000 words in a burst and then it'll be a good thing if I touch my fic again within a three-month span.
Recently though, I tried the trial for Scrivener and found out that it's actually helped me in being more consistent, so I decided to just buy it once I'd used up my free 30 days (every day you open the app counts as one day, so it did last me a bit longer than a month). I think the main reason being is that the application makes it super easy for me to write down a whole bunch of thoughts and constantly refer to them when I write as I write. I can also organise character, plot, etc. notes separately, and even do some cool search features so retroactively changing details doesn't feel like a trial in patience. The clunkiness of trying to manage a lot of Word docs was literally killing my urge to write!