Here's my two cents, and please feel free to pick and choose what you feel is important and what isn't, as all our roads are different, to say the least
I'm coming up on 15 years of playing, and I feel like I'm nowhere where I want to be. (Though this feeling seems to be common amongst us all) and for a solid 5 years of those 15 I just did good old fun cover band gigging. It was fun, and wouldn't trade it, but I definitely feel like I was having a good time but not improving and practicing fundamentals as much as I should have now.
I guess we guitarists feel like the years we play should be proportionate to the level of play, but that's certainly not the case. For me, when I really started to improve, was when I identified "What it is, that I want to be able to do with the guitar" this is the most important. Having a clear goal. We're all guitar players, but what we do with it is totally unique to each of us. Do I want to be a great blues player? Do I want to be a melodic lead player? Do I want to be a jazz/fusion improv player? Do I want to learn covers to my favorite tunes? Do I want to dig deep into theory/application to be a well rounded musician? Do I want to be a songwriter in X genre?
It's not so much that you must pick one or the other, but concentrating on one at a time, whilst giving good attention to fundamentals and technique will really help you to see progress, which is key to feeling satisfied.
This is where a good, rooted instructor/teacher is really useful. They'll help you pursue the ends you want to meet.Of course you don't have to, you could turn to teach yourself, and there's so many awesome instructional material out there.
So..... to cut my long-ridden babble short, and sum it up:
-Figure out what you want to do, and work at them one at a time
-Practice fundamentals (particular the ones that work in the goals you have, i.e. I want to be a great soloist, so practice alternate picking)
-Take a break every now and then
-Get a "good" teacher.
Good luck dude, I am in the same boat