I think the key to pattern mixing is having one big, bold print as the centerpiece, then adding more patterns in a smaller scale. For example, you could pair a polka dot dress like the one above with dotted tights. It's all about balance. Scarves are always a fun, easy ways to inject color and interest--throw on a bold patterned scarf with a striped tee and you're good to go. Look for colors in the patterns that compliment each other. Having said all that, though, there really is no right or wrong way to mix patterns. Just experiment, use your best judgement, and above all, have fun!