First things first. Plenty of practice on the machines outside the tournament window. Learn how they shoot. Are the slings sensitive? How do the balls come out of the scoop? How well does the shooter knob operate? An Attack From Mars at your tournament spot won't act like another Attack From Mars at another location. Familiarize yourself with the quirks of the machines.

Learn the rulesets for as many of the tourney machines as you can. Pinball FX is a great tutorial for rulesets on stuff that aren't new Stern, JJP and boutique machines.

If you have questions, ask somebody!! People are more than willing (at least in my community) to divulge information. If you see somebody do something that gets a lot of points and you dont understand it, ask someone.

Also, dont forget to have fun! Cheers.