Buy the Gleim ATP book.

Scan through the book and recognize some of the patterns in the answers (for instance 99% of the weight shift problems, the answer is the middle VALUE- ie a=135 b=124 c=167 answer is A)

Once you find some of the patterns, go through it with a dark marker or pencil or whatever and cross out all of the wrong answers under the questions (so that you can only see the correct answers).

Read through it several times and learn the answers- Rote memorization is your goal. Odds are 85% of the stuff in the written you'll never use again. (Even if you fly the 737 or 1900, you probably have an easier way to to performance and weight and balance).

Study hard for a day (like 6 hours straight), then go take the test.