A trick I have always used is to always have a cup of juice or non-alcoholic colored drink in my hand to make it look like I’m drinking. I even sip it slowly and make an after-taste face to be convincing. One time I even made it look like I was a taking a shot straight from a tequila bottle even though my thumb was blocking the eyelet opening of the bottle. It is very easy to fool drunk people into thinking your drinking, because they really don’t care anyway. The most important part, is to act relaxed and have fun like you are really drunk. If you act like you are drunk everyone will believe you are drunk. It is really easy because the happiness of drunks is contagious

There's nothing wrong with not wanting to drink at a party, just tell people the truth. Of all the parties I've been to I haven't really run into anybody that looks down on people that don't drink. As for drinking games, I guess you just can't play them. They are a great way to get to know people and flirt though.

A lot of the suggestions I've read thus far I wouldn't really recommend like "referring" a drinking game (by not drinking) and participating in a drinking game with something non-alcoholic. This is just going to make you look really lame to everyone around you, imo.

Drinking is not a big a deal to everyone at a party as you might think, just let people know it's not your thing and that you have a really good reason for not wanting to do it. Don't say the line "I'm having fun without drinking" because that just makes you sound stupid. If someone asks you why you aren't drinking just say "I don't drink." or something and brush it off like it's not a big deal, they're not going to pester you about it.