First and foremost, I'm in a similar situation, haven't shot compound for that long, that said, here are my thoughts. Spend some time with a good shooters getting real time pointers on form etc is a good way to head start (and continue). There are also a lot of good books to read, e.g "Bowhunters guide to better shooting" by Patrick Meitin, "core archery" by Larry Wise is another one. Personally, I don't have any pro-shops near where I live so I've relied a lot on reading and practicing solo and found it really good. If you haven't read it, here is another really insightful article:
http://archeryhistory.com/archerytalk/The_Nuts&Bolts_of_Archery.pdf
In terms of practice, I'd say less is more, early on, I'd shoot a ton of arrows without really putting any thought into it. Yes, I got better but it was more "gradual". Now I shoot fewer arrows but think more, focus on form, practice different aspects of the shot etc. Another helpful thing I've done recently is strapping a bag target to a backpack, hiked up in the mountains and practiced shooting steep angles , kneeling, under/between tree limbs etc. Super fun and you get a good workout hiking with the bag..
As it relates to gear, I've been shooting a somewhat mediocre fixed pin sight (started with 4 but added 3 pins), my next purchase will be a hybrid sight as I like the idea of having fixed short range pins, then being able to use a dial for the long range shots. I'd say start with your 4 pin sight and start doing research/figure out what suits you as you practice/get better. I often curse myself for not getting good gear right off the bat, but in this case I'm happy I didn't.
Finally, I'd say getting your bow tuned and making sure you're shooting the right spine etc would be another good first step. Knowing that your bow shoots straight eliminates a big factor.
Best of luck!
