How do i deal with my 3 year old son?

i am 20 years old and had him at 17 so i lack so good parenting skills in some areas of course. he is very spirited and i need advice on how to deal with him without breaking his spirit. my parents were so strict on me, which in the end turned me into a very shy person that was afraid to make friends and got picked on and was afraid to stand up myself, etc. so now im working on getting that spirit back. he is a very happy and outgoing child, but he has so much energy and it is very overwhelming to my husband and i. he is so hyper and bouncing off the walls all the time. he talks back to us, my mom (who will NOT put up with something like that normally, but he still manages to misbehave around her), my husband's parents, and just about everyone else. i have ed him, put him in the corner, tried talking to him and letting him know that that is not ok, etc. he is the sweetest little boy when he wants to be, but a mother's worst nightmare the next thing i know. going to the store can be a total nightmare when he doesnt get something he wants, he will scream really loud and its so embarring. any advice on how to properly discipline him without turning him into what i described earlier would be greatly appreciated. he starts school next year and i dont want him to be a discipline problem or a bully. please help!