Flying a model helicopter looks like a ton of fun, but it takes a great deal of skill to do it successfully. (Success means keeping the helicopter in the air and not crashing continually.) The best thing you can do to prepare for flying is to get an expert as a mentor. Go to your nearest hobby shop, chat with the staff and ask for names of advanced helicopter fliers. They’re usually glad to share their knowledge and start you off.
Even if you're a beginner, don't buy the cheapest model helicopter you can find. Bottom-of-the-line ones often won't hold together well, and it can be hard to find replacement parts for them.
Ask at your local hobby shop for a helicopter that's at least hobby grade--that means it has four channels (throttle for up and down movement; yaw for flat turns; one cyclic for right and left movement and the other cyclic for forward and back movement). More advanced helicopters come with more channels, but beginners often start with four.
Take your time to master each step. For example, become proficient at hovering before you move the helicopter forward and back or try to make turns. Restraining yourself won't be easy, but it will save you money and frustration. (The money will go for replacement parts.)
Carefully read the manufacturer's instructions--especially the safety rules. Turn your radio on first, and then plug in the battery. Wait at least 10 seconds.
Use the throttle to raise the helicopter about 3 feet off the ground. You want to hover at that height because if the helicopter is much lower, you'll get "ground effect"--instability due to turbulence close to the ground. Practice throttle control until you feel confident.
When you're ready, use the cyclic and yaw channels to move and turn the helicopter. Fly it with the tail toward you; that way, it will turn logically in the direction you want. When you're more advanced, you can try other things, but tail toward you makes it easy to start.