1) Put some of your old clothes away for a year or so and then, when you're feeling the need for something new, bring them out again.
I'd originally done it because I don't have next to no drawer space, and now with the weather changing I've rediscovered and adopted them back. People have been complimenting me on three-year-old clothes that I used to wear quite frequently, and saying "good, you finally went shopping!" (um yeah, three years ago at Ross, lol).
2) Force yourself to combine your favorite, frequently-worn clothes into new and exciting outfits. I'm putting things together that I'd never even thought of, and the result is a whole new collection of exciting, becoming outfits that make me feel like all the clothes are new.
Yeah, a couple things about me: I love to dress up, but I despise clothes shopping and have no money anyway.
Hence these tricks--looking new and nice without the time and money!