Forever 21 has really cute clothes in all the very latest fashions. If you see something you like in Vogue or Cosmo and want to copy it, Forever 21 is a great place to look. They are constantly getting in new items so it's worth shopping there frequently.
Their prices are amazing. Most items run less than $50, so you can put together several outfits for less than one actual designer piece would cost. They have accessories and jewelry, too, so you can create an entire "look." Their staff is helpful and honest, and they'll assist you in finding something that looks fabulous on you.