The pinky problem

Try practicing the chromatic scales. It puts all your fingers to work and makes your pinky more agile. Also try string bending with your pinky. That will really make it strong and firm.

I used to have this problem as well but I have found a few ways to strengthen this little finger. An exercise/warm-up that you can do is to use all four fingers and play four consecutive frets (one using each finger). 1st finger = first fret, 2nd finger = second fret, and so on. You can do this for each of the strings as well. Playing with alternate picking while doing this helps grow your picking skills as well. I have found this to really help. Also, find and learn some chords that involve the pinky finger. This way, in order to play the chord, you will be forced to use that finger. Change from chord to chord while playing and you should see yourself improve. I hope that helps! :) Happy playing!

It's simple, really - Make yourself use it more often. See, there's an easy trick to get over any 'bad habits' or problems when you're playing guitar. Make yourself get over it. For example, if I decide that I need to work on my trilling technique, I'd write out an exercise with excessive trilling, and play it constantly. In your case, a good idea would be to write something that -requires- excessive use of your pinky, and just go at it for an hour or so. That's definitely the best way. Good luck!