1. Slowly does it. I’m not a big fan of metronomes but what I would recommend is to play or practice a scale at a speed which is technically comfortable for you. By this I mean as fast as you can play it without making any mistakes or clams. Speed comes naturally, an important factor of which is control, and this is what you’re grafting here.
2. Practice what you preach. When practicing scales play stuff you would actually play live or during a solo, if you’ve already got the pattern under your fingers. There is little point endlessly running up and down scale patterns as what you practice will inevitably show up in your playing.
3. No pain, no gain. You will of course have met those guitarists of the ‘no pain, no gain’ persuasion who will run guitar scales until they have a borderline case of tendonitis. Music is not a sport. I remember one guy in colllege whose tendonitis got so bad he couldn’t even lift up a beer glass. Golden rule: if it hurts, stop and take a break.
5. Root notes. Part of the reason I came up with the 2 Position System was to create a way to access any guitar scale pattern without having to rely on the E or A string root note. This is especially a disadvantage of the CAGED and 3NPS systems where the root notes get lost in the clunky patterns causing an unhealthy dependence on the lower strings. Ideally you should be able to ‘see’ the patterns so clearly that you can approach them from any angle, hence the advantage of using one octave patterns.
6. Push yourself. Never get complacent, each scale is a world of infinite possibilities worthy of exploration and their applications as varied as there are players. Try it with the blues scale, see if you can come up with something that doesn’t sound like a cliché.
7. Let your ear take over. When you feel very comfortable with a scale let your ear take the reins and dictate what your fingers do next. Again, the 2 Position Patterns are excellent for this as you’re not focusing on a huge selection of notes. You’ll know when your ear takes over, it’ll give you chills.
8. Chromatics. Don’t be afraid to throw in the odd chromatic note here and there when playing any guitar scale. They add color and only by experimenting will you get to know which ones work better with which scales. This is especially useful if one of your goals to be able to play jazz.
9. Use your pinky. Don’t neglect your pinky when playing scales, incorporate it from the start in order to build the habit and the strength to use it. A great exercise for this is to play without using your index finger. It hurts at first but it forces the pinky to work.
10. Apply new knowledge. Play along to songs or put on a backing track and just go for it. It’s critical to start incorporating any new guitar scale knowledge into your playing. It may seem a little forced at first but it will soon become second nature.
Above all have fun with this stuff.