Changes

Well, firstly, you must be sure that you are not afraid to hitchhike. If you are, you will either look very dark and quite and the driver will think you are a road thug, or you will rapidly start laughing weirdly which would make you look like a dumb. Don't be shy, but not too confident either, that would annoy drivers. Find a good place to hitchhike, could be a gas station (my favorite, at least) or or near a large sign. If it is hot, always stay in the cool-shaded places. Make sure you are not in the middle of the road, or it may risk your life. Wear bright clothes, so drivers can see you from a distance. Having a cardboard is also a good idea, and humorous ones work really well, as it catches eye. The rest is just about giving a thumb sign, and wait for a nice [ or lonely :) ] driver to pick you up. After he/she approaches, ask where he/she is going, be polite, and enjoy the ride (not too much, or you'll annoy the driver). And whatever you do, don't panic.

* And at last, but definitely not the least, the ultimate edition of "The Hitchhiker's Guide to the Galaxy" by Douglas Adams.It kills time quite good, and its very funny, even tough it has nothing to do with hitchhiking, and avoids getting bored in long journeys. DON'T PANIC :D