Question: I have two problems: firstly, when I'm learning scales should I learn the full scale or just learn it at a particular fret. Secondly, how can I build speed on guitar. Also how should I go about building riffs and solos?
Answer
Learning the full scale (as in the scale's pattern right across the fretboard) might be a bit overwhelming at first so I recommend starting with the 1st position boxed pattern. This can be at any fret to begin with as you're just getting to know the scale's intervals/flavour.
The video and lesson below gives you a good step-by-step process for mastering scales across the entire fretboard...
Speed is something that comes naturally the more confident you become with a scale's pattern and function. So don't think about speed as a practical goal, rather be reassured that you WILL speed up over time.
There are techniques that support speed playing once you know the scale inside out.
Legato playing, for example, is about using hammer ons and pull offs to slur your scale phrases.
Practicing scale runs also helps build your speed with alternate picking.
If you're a metal fan, try the lesson on fast picking.
Check out the lead guitar lessons section for a library of exercises that will help you with speed.
And of course, it's important to use a metronome to start slow and gradually speed up. Only increase the tempo when you can nail a given exercise flawlessly.
