I've never bowled the USBC Open, aka Nationals, but if I were to do it, I think I'd like to approach it the way Richard Eisenhut of Downers Grove, Illinois did this year. Eisenhut has taken the early lead in the Classified All-Events category with a 600 series in doubles, 587 in singles, and 579 in team for a 1766 total. This is much better than he's ever done before, and, even though he doesn't expect his score to hold up as the top score, he's very pleased with his results.
How did he do it? He prepared for the tournament with the help of Bronze Level coach and former Open champion Gregg Zicha. He worked on improving his execution, strategy, and ball selection, and he practiced on conditions similar to those at the Open. "We put out the shot and talked about where to play and what moves to make," explains Eisenhut.
I don't think the USBC releases precise details about the oil pattern they use at the Nationals, and, even if they did, it's surely not possible to simulate the conditions perfectly in another bowling center with a different surface on its lanes and other differences. Nevertheless, a skilled coach could probably gain a pretty good idea of what the pattern is, have it put out on a practice pair at a local center, and help you learn to play that pattern better than you'd know how to play it without the assistance.
This seems like a pretty good way to go, kind of like practicing with expert coaching for the SAT or GRE before taking it for real.
If you'd like to read more about this story, click on here.