Go to a few races and find some folks who will answer all your questions. As discussed on this thread, there is a LOT to learn.
As to getting under that index, a lot will have to do with how "soft" the hp factor for your combo is. If it's factored relatively high, you'll have a really hard (expensive) time getting under the index. There are some combos that are factored relatively lower, which will make it easier to get under the index. Learning how to search the classification guide is key. You also have to know if a given combo is even in the guide.
If you pick the wrong combo, you'll be fighting yourself from the get-go.
If you're going to build a legal combo, but just bracket race it as you work on it, that's an option.
Once again, there is a WHOLE LOT to it. If it were easy, everybody would be doing it.
