This will tell you how to look good in any old outfit .If you have boring old clothes, don't throw them away. Read this and then customize them.

[edit] Steps

Take a look at some recent celebrity magazines and look at what they are wearing. Single out a few styles you like and experiment. Make sure you choose a style that suits you. For example, if you are a girlish blond who won't get her hair dyed, you might not want to go for a Kelly Osbourne look.
Make sure you can afford it or can find a way to customize old items.
Buy one outfit. For example, if you are turning hippie, just get one miniskirt and top, and then maybe a few hair accessories. If you are sure you will like your new style, then carry on.
Prepare to go shopping; before you go, look at your old wardrobe and take some to see if you can reuse and redecorate some of it.
Buy as many outfits as possible (within a reasonable budget) and then get started on the accessories.
Take a trip to the hair dressers and get a cool new hair style that will get you noticed.
Do your make-up and look nice, then walk proudly in your new style!

[edit] Tips

Learn how to sew if you can't already. It will be useful for sewing stuff onto jeans, bags, tops and other things. Beads and old pieces of material can make old things look brand new!
Be confident. If you are a little overweight try and lose a few pounds it will really make the difference!
The denim miniskirt will always make you look nice.