Keep it Off the Net
Of course, that's only possible if you can get all of your friends with cameras to agree to never post pictures that include you to the web.
As well as family.
And public officials.
And personal enemies.
And other people who know you.
And anyone who doesn't know you who you might conceivably meet some day during your lifetime for some reason.
And the only way to make sure all these people (read: far too many people to be practical) don't post pics of you is to constantly monitor the entire internet 24x7 and report any pictures of you that you find inappropriate to the responsible websites immediately, in the hopes that your tying speed is faster then whatever archiving/data storing methods said website uses.
The other option we currently have is to simply say "f**k it" and assume that we're GOING to be exposed in an embarasing fashion some time on the internet. In which case, you simply live as best as you can, and when the inevitable happens, you either hope the problem eventually goes away on its own (and suffer the social stigma/job loss/etc that come with it) or you shuck everything you've ever known and loved, and start over with an entirely new identity (location, physical appearance, name and bio, etc).
At least, that's the choice being presented to us by those in charge. Really wish there was some third option, but with company, government and cultural attitudes towards the internet and data archiving, there currently isn't.