First thing to do is build up your mental cushion for aa (look this up if you dont know) and the best way I did this *I do this when ever I need a pick up on my inner game. Inner game is something you need later on *for multiple approaches and LTR (long term relationships), you need to just focus on saying hi for now.
My AA cushion (because AA never really goes away) is to stop sarging, and everyday, yes EVERYDAY for at least a month, you need to go to a populated place and compliment 5 people (guys / girls it doesnt matter) on an item, or on a clothing piece of theirs. Anything is good except physical beauty (ex. hair, smile, boobs, eyes, etc... no body parts, this isn't extra credit for anatomy class, so dont bring it up).
Ex:
you:Oh excuse me I just wanted to stop you to ask you where you got your shoes, they look nice.
person:thank you, i got them at such and such a store
you:thanks for the tip
and then you walk off...
if they dont answer *could be a bad day, or you approach wrong* [approach like a walmart salesman; a smile, tall and erect, and a good amount of space between the client / target]
then you should view the blow out as its that person's loss, not mine. there are many more people out there to accept your compliement, and the best thing is when they do you both will feel great! 
What a friend did, was set the AA bar down to complimenting five guys and then build your confidence and then go up to five ug (ugly girls), then five cute girls and finally five hot babes. Once you do this for a month, go and try sarging and see how much your better your game is
(always improves the game).