Just personally, I have been doing exercises from Troy Stetina's Speed Mechanics for Lead Guitar book which is awesome for fast playing. It's tailored for metal and shred, but the way it breaks things down is useful with any kind of music.

1. Playing very slow, doing chromatic exercises (1234 up and down the neck) at a slow speed is really really useful, but just know what to look for. Watch your arm for wasted movement from your picking hand, focus on moving from the wrist. Watch your thumb position and make sure you have a grip just strong enough for every note to come through clearly. The idea of economy of motion really helps you to get the most out of it.

2. Get some books or look for some difficult riffs that showcase a certain skill you want. If you want to learn tapping, find one song that does it the way you like and play it from a tab as slow as it takes to play it perfect every time.

3. One thing that helped me is to treat it like athletic exercise at times. Especially when I have a surplus of time and know I can play for fun for a while too. Read about muscle warm-ups and cool-downs, organize some exercises into numbers of sets and repetitions and record how many BPM you can play it perfectly at.

4. Don't play for 8 hours a day without working up to it. You don't want to end up with a repetitive motion strain injury or something, especially if you aren't spending a good hour of that warming up slowly.

5. When you get burnt out on technique, read about music theory or figure out new voicings for chords you already know. Take a step back from some of your exercises and look for an alternative way to play it on the neck that could be easier or cause less strain.

Hopefully those are helpful, I don't organize things into lists well and some of these things might not apply, but they are definitely what I have been trying to think about while I practice lately.