I want to be able to just play solos in a certain scale, but what is the best way to learn scales? Is it in the block shapes or just learn the fret board?
A few steps.
- Learn the theory so you know what the notes are. This will enable you to figure out the shapes for yourself and get a good idea of what chords will go well with you solo.
- Learn the shapes
- Don't stymie creativity by only doing scales in one position. Do them in one, two and three string patterns. Start on your 1st, 2nd and even 4th left hand fingers. One, Two and three octaves. Certain phrases will simply just work better in some positions than other. We want to be able let the music decide the position not just a lack of knowledge / skill.
- Do scales in basic and non basic rhythms. Adding rhytm to the mix will change your scales from scales to music. Practice not just basic four time but also compound time, Duplets ( 2 in 3's time), Triplets( 3 in in 2's time) and even six in four's time.
- Be patient with your metronome work. The more patience you use here the better you will be. I have a rule that you should in 2 - 3 days of practice only go 5 bpm faster on the metronome. The more time you spend on each of the metronomes beats the better skilled you will become.
This first part applies to all the string instruments, not just the guitar.
Most people that play guitar/bass/double bass etc learn the certain shapes that each scales consist of. This has a great benefit: you can easily transpose to any other key.
For instance, if you know the shape for a major scale, and you practice it in C major, you can easily go to Ab and play the exact same shape and you would get the Ab major scale! Saves a lot of time in trying to remember what the key signature is etc.
Of course you can also memorize the fretboard, but this would take more time. By learning the shapes of the scales, you would eventually learn the fretboard as well.
Another thing you can do, is to remember the interval sequence for each scale. Like, for a major scale you have W,W,H,W,W,W,H (where W= whole step and H= half step). Now, if you memorize this, you can easily play any major scale, without trying to remember the key signature to each. You can apply this to any instrument and theoretically too
I agree with others here to learn shapes first. There are plenty of resources on the internet to get diagrams. You will be learning the fretboard as you go along learning shapes. The shapes as you will see connect across the fretboard. Also, you will build muscle memory in the hand and it will be easier to solo in the future.
As has been noted above, the guitar is a shape-based instrument. So learn the shapes first.
But the shapes tend to connect across the fretboard. So after you learn the shapes, learn to connect shapes adjacent to one another by any string.
Now you can play up and down the fretboard. But the strongest notes you can play in a solo are the chord tones so learn the chord shapes within each scale shape. Learn the notes for each chord shape, especially concentrating on the roots and thirds. This is often called the CAGED system for the four different chord shapes.
Finally learn the positions of all of the notes on the E and A strings.
If you learn all the shapes and the notes, then at the end you have learned the fretboard.
The guitar is very block/box orientated, and lends itself well to learning in shapes. You'll need to know notes (some), in order to find start points, but I feel there is no need to know each note as you play it. The reference against the previous and following notes is more important.
Shapes, and not just the "box" or "three notes per string," but also learn the intervals and the shape of the scale up and down each string. This will allow you to connect boxes and also to play some cool sliding-around solos without getting lost.