Pick on some more notes to add to your repetoir, that are related to what you are doing, and that which you have discovered whilst doing the first thing.i.e perhaps the next string on the guitar,(it happens to be the B string(second),Find the point of crossing over from one string to another, ie the correct interval below the one you are playing on the E string.,and take it from there, the self same thing.
You can find a cross over point on all six strings, in the first 2 oe 3 frets of a guitar.Eighteen notes play around with!
Another exercise worth doing, is to "Discover" your instrument, and get friendly with it.
Discover the "Full Range" of notes on your instrument.
On the guitar,This will be 16 notes, up to the 5th fret of the highest string on your guitar,(the E string),from the lowest string,(also an E string).You can additionally to these notes, add whatevr you can discover above this 5th fret of the high string,which, depending on the length of your guitars neck.On my guitar there are 10 more intervals,(notes).
This straight off, gives you 26 differrant notes, to fire away with.
You are ready to have a sensible conversation with someone who really understands.Yourself!
Play away your thoughts, They are translated to the secret Language!