Hi everyone, first post on these forums.
madman3123 says:
say i have a chord progression in the c major scale lets say Cmaj Gmaj Dm Am (kinda random) how would i complement those chords in a solo?
In addition to what JazzMaverick's said about playing the notes of the chords and adding passing notes, I'd say that every good solo starts with some kind of theme. It may be just a repetition of the verse or chorus melody, or a fragment of the melody which you'll turn into a theme/riff by repetition. You establish it, vary it (i.e. depart from it), then return to it.
For example, let's say you just extract a single measure from the song's melody and play it during the C major chord. Now when you move to G major, you can just adjust any C or E notes in the riff to B and D to match the new chord. And slide any passing tones (non-chord notes) in the same direction. Then do the same as you move to Dm and Am. It'll be a tad dull or formulaic, but that's fine for the initial statement of your solo - to some extent you really do want to drill your theme into the audience's head before you depart from it and eventually return to it.
For variety, don't use the suggestion in another reply where F-A-C notes are randomly played on top of the C major (C-E-G) chord. If you want to add new notes but still "fit", think about extended chords. So your C - G - Dm - Am progression might become a Cmaj7 - Gadd2 - Dm9 - Am7. You've now added the note B as a new "legal" note during the C chord, an A during the G chord, both a C and E during the Dm chord, and a G during the Am chord.
If your chord progression is already using extended chords, you might start thinking about tritone substitution to open up new harmonic possibilities. If the progression was Cmaj7 - A7 - Dm7 - G9 (I swapped your A & G chord locations to imply a cadence back to C at the end), maybe an Eb7 could work in place of the A7, and a Db7 in place of the G9. This could lead to a nice "slide" of Cmaj7 - Eb7 - Dm7 - Db7. Once you've substituted those new chords in, you can vary your lead work to use the new pitches available.
Hope those ideas help.
- Jim in Austin, TX