I'm pretty much in sync with Shimmer on this one.
Being consistent and firm with your decisions, learning what will hold his attention so that you can redirect when he's doing something he's not supposed to, knowing when he's being a brat or when there's really something wrong [tired, hungry, hurt, or just plain sad]. Staying level headed is most important, I know they work our nerves, but usually the vibes you give out are the ones you get back, so just try your best to keep your nerves.
I have a 1 and 1/2 year old daughter and she's learning the joys of "NO!", climbing on tables, throwing food LOL I notice that when I just dismiss the behavior or deal with it calmly, depending on what she's doing, it decreases.
Best of luck.