How Do You Avoid Glare When You Take A Picture?

QUESTION:   How do you take a good picture without getting glare?  I've been trying to take pictures of things that are framed with glass on them, and can't figure out how to do that without either seeing myself in the picture or having to use such a weird angle that I don't really capture the look I want.

I'm hoping for some good tips/pointers from you photographers out there!