Welcome to the addiction!
There are a couple of things you can do...
1) Check farecompare.com/flyertalk everyday. It will usually know where you are and find the best cpm deals from your departure city
2) Keep up to date on the Mileage Run Deals site and see if any cities have offers too good to pass up and find a way to get there (e.g. last year, a lot of people on DL did this when the double MQM promo was going on from select cities)