When you are doing this type of soloing it is easy to get caught up in the technical aspect. Remember to keep your musical ideas simple at first.
Making a blues riff
Pick a simple riff from the blues scale on the 3rd fret that is four beats long.
Now play the same, simple riff up at the next spot (the 8th fret). Then play it at the next chord (10th fret). Then play it back at the C chord (8th fret).
Now play the chords once through. Then play another riff and repeat.
Remember to keep things simple and keep the beat going.
When using this method of soloing, alter the melody slightly each time for emphasis, contrast and syncopation.
You can try to do the same thing but make a riff that this is more bass-like and groovy.
Exercises
How to shift
Play the first note or chord in the first position
Relax your left hand
At the same slide your hand to next position on the guitar neck
Your thumb should just barely brush that back of the neck