Funny thing is, you rarely here about anyone explaining how to be a GOOD sport. It's obvious that there are players out there with bad attitudes, but it's rare that someone gets complimented for being such a good sport. First of all, being a good sport carries with it a lot of things. I pride myself on being a good sport. Being nice to my opponents has gained me a lot of respect.
Common courtesy is the biggest hurdle for some people to get over.
Just try not to be offensive. Keep the idea of the game in perspective. It's very easy to be competitive and still have a fun game. It also will make you feel good to be the benchmark of how players should be. People will even get to the point that they look forward to playing you.