How to do the Frontside 180
Before you do the Frontside 180 you have to be able to Ollie, and you have to be kool at riding the board in switch position. That means having your feet in the switch position which is having your back foot mostly square on the tail. Your toes should on the board but right on the frontside edge.
Your front foot is really important because you will be using it to control the board during the trick. It should be just behind the bolts.
This trick is different from an ollie in that your wind up for it. This means that you turn your shoulders opposite of the direction your going to spin before you pop the tail. You only need to turn them a little bit to do a 180 so don't overdo it. When your setup, start to turn your shoulders in the direction of your spin and pop the tail when your shoulders are back to parallel with the board. Timing of this is really important. Your feet now act like a regular ollie. Your shoulder turn will turn our body but it probably wont bring you all the way around... this is where your feet come in. You will want to guide the deck around so that you are landing 180 to the the direction you started. You always want to turn your body before trying to turn the skateboard.
At first you probably won't turn 180 degrees. It takes some time and practice. You don't want to over rotate your body because that makes landing a hella lot harder.
Like all tricks that you land you want to keep your feet over the trucks. Let the trucks take your weight (you will break a lot fewer decks this way) and let your knees bend.