These are things I've learned along the way, and thought i'd be effective to compile a list of do's and don't and how to travel on a budget.
This is the largest portion of your budget, so here are a few tips to help you save:
1. The cheapest day to fly is Wednesday, followed by Tuesdays & Saturday
2. The most expensive days to fly are Friday & Sunday
3. Search for nearby airports - For example, if flying to San Francisco you could search Oakland (and take the Bart to San Francisco in a few minutes). If flying to Europe, it's sometimes cheaper to fly to London and take a train between countries or a low cost carrier like Ryan Air.
4. Don't limit yourself. Most people search Orbitz, Expedia, etc... I always search Kayak, then I go to the airlines website and check directly.
5. Sign up for Airfarewatchdog.com (they will email you daily fares from your particular city)