Hey OP, writer here, the best course of action is to decide what you want to do before you go out. For me, and many others, it was a simple (and shitty) tag. Practice writing your tag by completely filling a few dozen sheets of paper with it. This will help you get used to it, obviously, and it will also let you make any changes in your lettering style before you go out and do something you'll regret. I started with just writing on road signs with a very reliable sharpie.
Since you're apparently a beginner, start small. You're going to do a lot of work that you might not actually want to be representative of your skill as an artist. The best place to get some practise is by taking your cans and making shitty little pictures on dumpsters and inside abandoned buildings. Eventually you'll get to a point where you are comfortable with your regular tag or character or fucking whatever. Next step for you would be to go find a ravine or some dirty alley or hang out under a bridge and go nuts with what you've got. A friend of mine went from practicing in ravines and under bridges to going into the bathrooms in fast food places and writing his tag a few dozen times all over the mirror and the walls
As for choosing what paint, it really doesn't matter. Feel free to try a variety of different cans and brands and find one that works for you, but generally anything that sprays in a nice, tight cone works best
good luck you wannabe street faggot
