Welcome to Flyertalk! To build upon tom911's solid advice:

Acquaint yourself with Flyertalk, then definitely check out expertflyer. If you fly much, you'll get your value from the $100 annual fee in no time. Many posters here don't even buy tickets until they are sure they'll be able to upgrade, so having a tool like expertflyer to do one's own legwork is huge. Personally, I don't often upgrade international flights, but I use it to look for fare availability, look for award tickets, and check loads to see if bumps look likely. There are plenty of other threads in which people describe how they use it and it has helped them; I think you're unlikely to find many dissatisfied customers.