Practice on a clean channel. Always. Even if it's heavy style music, listening to the notes really ring is something that's always helped me. And slow - I found myself always subject to doing the same or semi-same lightning fast runs, but guess what? After a couple years, that's all I did - the same lightning fast runs. Somebody would demonstrate something else and I was like a fish out of water. So I canned the 'runs of the year' and got into stuff I didn't normally play.
Picking. Real good technique for alternate picking and NEVER screw up your timing - always always always down up down up down up (or up down up down, you get the idea). Do this slow, and the surgical precision you'll get after 20 hours in is pretty awesome.
When jamming or gigging, less gain. Sounds much better to the audience (or mics for that matter), cuts through, and due to the roundness and color of the notes not being mashed with tons of compression, when you DO go through a fast, perfectly plucked run or hard-down legato, the notes are super percussive and tight.
Funny, I write ALL this down yet I am my own worst enemy. I still do all my bad habits when I've got limited time with the guitar. Funny that... Also, if you do allocate practice time, section it off with a clock or a timer; don't dawdle on stuff - go through it, do the best you can, and then move on to the next step. A friend of mine who's an INCREDIBLE guitarist (classically trained, just fn SICK!!) told me this - and I couldn't quite understand what he was getting at. But bottom line, we learn nothing by repeating shit we already know - warm up, do 20 minutes of arpeggios, do 20 minutes of alternate picking scales; do 20 minutes of long stretch classical chords; and do 20 minutes of noodling. And whenever LEARNING a song, LEARN IT from front to back - no matter HOW boring it gets in between (as it's how you maintain these boring in between bits that really works on your tempo, consistency and - tightness!!).
Peace,
V.
PS - and last but not least, less grip on the neck - less pressure on the finger tips - makes for smoother runs, less fatigue and better accuracy when you're relaxed.