These are great suggestions everyone- thanks for sharing. Here are a few more:
1. For the small business owner remember that you can earn miles for your business and for yourself. Example: Alaska Air has EasyBiz, an online option for small businesses to buy tickets and earn company miles. The traveler (you) still earn your miles for the trip and the site allows you to make changes, exchange tickets and manage your account. Of course, you pay for your ticket with your Alaska Air Visa and you double your miles.

2. Check out your frequent flyer membership websites and subscribe to the e-newsletters. Most offer the subscribers special discounts and alert you to double-mile promotions and fare sales.

3. Earn enough miles to be elite on at least one airline to utilize the 'fast line' though security. This way no matter what airline you fly, you will get through the line first. I fundraise for charity and have sold a one year elite card for over $10,000 - they are so valuable just for the 'fast line'.