Use a belt
You can always add some style to an old dress by adding a belt to add a little something extra. You don't have to use a belt only, a time, scarf or sash will work just as well.
Don't spend money on the latest cropped trousers. Roll up your old jeans.
Mismatch is all the rage this year. Don't worry about wearing matching earings. Just throw on any old mismatched pair. You can try different combinations until you are confident of making a wacky but chic statement.