Here is a couple of finger exercises for guitar / bass that I was taught years ago and I still swear by them now. Although they do not sound particularly melodic they are great for coordinating your fingers, especially your little finger.
Try these along with my backing tracks on my ‘Get your riffs and licks up to speed‘ page and this could be a winning combination.
Exercise 1. Chromatic scale
Remember to use all 4 fingers, and alternate picking!

Exercise 2. Mirror images.
For the top line, only hold down one note at a time remembering to move up a fret every 8 notes. For the bottom line play the chords and see how quickly and confidently you can change, it really is harder than it looks, especially at speed but it’s a good challenge nonetheless.

More next time.

