Be patient. It's going to be frustrating at first, but you'll get there. Trust me. Acoustic is more difficult, because the strings are a bit harder to press down, but when you eventually pick up an electric, you'll be shredding! It's best to learn on an acoustic.
As you're practicing, use all of your fingers. Building pinky/ring finger strength will be the most difficult, but the more you use them, the stronger they will become. Also, try to keep your thumb from "hanging" over the neck unless you need to mute a string. Keep your thumb behind the neck, this will allow your fingers to stretch and operate better.
Other than that, just keep practicing. Your fingers will hurt at first, but once your skin toughens up, the pain will go away. Don't expect to be playing full songs (or even full chords) at first. It took me a good couple of years to play a whole song correctly.