Also, focus more on postcard entries rather than 3x5 entries. You can get in more entries for your dollar. Enter sweepstakes that have more than one grand prize. Sure, the prize for a sweepstakes with the single grand prize might be nice, but your chances of winning will be better for a sweepstakes that offers multiple prizes. Try to enter at least once for snail-mail sweepstakes that you are interested in, and enter a few more times for those sweepstakes that you are VERY interested in.
Contests are good to focus on, too.
There is always less competition for contests because they take more effort to enter. As your budget increases, enter more snail-mail sweeps. For example, here's our approach. For every sweepstakes that we are eligible to enter, we enter at least once or twice for the ones we are interested in. If we are VERY interested in the prizes, we'll enter about 5 to 10 times.