Many on these boards (but not all!), travel for work weekly, so it is on the company's tab and the airline miles and hotel points add up quickly that can be used for 'free' travel. Otherwise you need to travel a lot on your own dime to get miles for free tickets. Some people have found a gift for finding low fares for mileage runs that help too. Credit card offers, partner offers, etc will also boost your mile totals.

Besides accumulating miles, try to get bumped off your flight and earn free trips. These days airlines are over-selling flights in the hope to fill every seat after people miss connections or cancel at the last minute. In many cases airlines ask for volunteers to give up their seat in exchange for a seat on a later flight + vouchers or free trips for future travel. Some flight patterms always over sell and others never do.

Hope that helps and good luck.