We've been pulling for close to ten years now at all the local fairs. My brother in law has been nice enough to donate his trucks to the local dirt....

First of all, most "stock" trucks are not set up to pull correctly, so any further comments I have will pertain to stock trucks (aside from power adding devises). Also, this applies to an F250, not 350. The 350's sit classicly higher in the rear, and this changes EVERYTHING.....

1) Practice makes perfect. Just like any other sport. Every pull you do, you learn more, and pull further/better. No questions
2) With a stock truck (stock suspension) and no weight on the front bumper, the higher hitch in the rear always hurt us. Picture the back tires being like the center of a see-saw. When you floor it, the truck digs and lifts the front end up. The higher the hitch, the harder it pushes on the back, the LESS traction you have in the front. For a stocker, we always take it about an inch or two below max height.
3) Here's a big one. The trailer. Some advance weight by time, and others advance weight by distance. If you've got some good horsepower, we have found that if it's by time, run the truck in high range, first gear, and get out there faster. By the time the weight comes on, your haulin a$$. Tough to stop that weight at 30mph.... If it's by distance, the weight starts to come on hard at maybe 1/3 track or so... In that case, you want the truck in low range.
4) Tire pressure. If the hitch is about 1-2 inches below max, run the tires low for traction. We tried full PSI (only because we have the horsepower to spin them hard), but all it did was wheel hop the front end something so fierce it would make any Ford owner cry.......

As far as what gear........ These trucks have AWESOME power....... when Ford wants you to have it. I feel that if these trucks were to ever shift into 2nd gear, you would fall out of the power band something fierce and never recover. On the other hand, if you started to see the rpm's drop, you could just push the button down to 1st or something. For the record, I don't think you should or could start in second, even in low range, but everything's worth a try.

Post up your truck details, and which Fair your pulling in. If I can see the trailer, or get specs on the track, I may be able to throw you a decent receipe to at least get you moving. I always find that truck pullers are a great bunch of guys too. Your best bet is probably palling around in the pits. Find a guy that's got a similiar based truck. Grab two beers, and go chat with him....