Like above have said, it really isn't that hard, when you've deveoped finger strength.
First off, try using your 3rd and 4th finger, as these will probably be your strongest fingers. Make sure you're hitting the string with the right part of your finger; right on the tip. Practice with slurs:
Pick, say the D string, and then hammer on the 2nd fret. Do this quickly, but comfortably. There should be a fluid motion/sound.
