Why the hell would anybody want to put their life in danger and hitchhike? We'll mostly because it's free and it still carries this cowboy culture that a lot of people romanticize and respect.Thumbing your way across the country is quite an experience. If you're going to do something like this you have to be prepared to go through hell. In the long run though it's all worth it and it's an amazing memory.
Step one: Pack your bags. If you can bring only what you need and if possible send your non essential baggage ahead through the mail. It's an expense but it's better than having to carry it all and risk it getting stolen. You're going to need a place to sleep like a tent or sleeping bag, anything you need to cook and start fires, clothing for the climate you're going through, and the all important large tipped sharpie pen. Make sure this bag can sit on your lap for twenty hours comfortably.
Step two: Plan out your ride. Make sure you carry a map of the whole country you're traveling through with major roads and highways. Pick a route and stay on it as best as you can, it's ok to adapt but there's no sense in getting lost or going way out of your way. Google maps is your best friend when it comes to choosing routes. If somebody isn't going your way turn down the ride, there's always the next car.
Step three: Pick your first location to get your ride. Gas stations and intersections near highways are great places to find rides. Don't stand by the on ramp, the cops will pick you up, it's happened to me before.
Step four: Stick out that thumb! The hardest thing about getting a ride is that people seem to hate you. Maybe not but after four hours standing at the road you start to think so. Even worse when cars will pull over to pretend to pick you up and then speed off. BUT it is possible to get a ride as hard as it seems. Make a sign with clear bold letters of where you want to go. If you're traveling large distances only put a few towns over and just try to hop from large cities. Some people like to put some flair into it by dancing, waving their arms and signs around, and putting jokes on the sign next to their destination.
Step 4.5: Ways to improve your chances of getting that ride. If you're a man it's best to travel alone or with a woman. Not very many people are trusting groups of strange men in their car. If you're a woman you should bring a friend, preferably a man to protect you from sexual advances. Try to keep clean and look normal, nothing will turn people off more than ragged clothing, a shabby beard, and that cowboy hat.
Step five: Safety. First things first, no matter how long you've been waiting for that ride, when you think something is fishy don't get in. I've had EMTs tell me stories of finding stabbed and raped hitchhikers. It's still a dangerous journey so it's best to be prepared for danger. So I recommend sticking a knife in your bag even if it is illegal, the cops can't check unless you're doing something illegal or give them permission. Another thing to carry is a can of pepper spray, it's very effective in a car. So effective I might add that you're probably going to get some in your face too. If you can't get pepper spray a film canister full of finely ground pepper works on the fly.
When you get into a car always check the handle when the door closes and check for a childlock if you get into a back seat. Keep you bag on your lap and if you stick it in the back make sure you can lose everything in that bag and not care. It's a huge risk that you're going to lose it. If you're in a car and they refuse to pull over a easy way to make them slow down is to take a roll of toilet paper, light on fire, and throw it in the back seat. Another risky way is to yank the wheel force them off the road. The point is to slow the vehicle enough to bail out and roll.
Have fun and always remember: safety safety safety!