How I did it: I watched when tickets were on sale for about a year with no success. Fearing the ticket resales on the internet I waited to buy them through the BEARS online the day they went on sale. Everything under $250 was bought for all of the reasonably warm days, so I found a date that worked with my schedule and bought them!
Lessons & tips: Research and commit. It is always more fun to see a game where the team you love is winning, but be prepared to enjoy the experience and not just the game. Remember it is still the team you love. I guess I am sounding more like a Cubs fan than a Bears fan ( :) ) but it is important be prepared for what comes with a "GAME."
Resources: Be prepared to spend alot or buy early. I would try something like StubHub if I had heard it was good. It was definately useful to keep searching online, because that is how I found out about the shuttle running from my suburbs to the stadium directly for only $4 each. It was so much easier than driving!