Wear the right kind of clothes for your body.
Don't buy clothes that are too tight or too short. It won't look nice, especially if you don't have a thin figure. Good clothing often starts with the fit.
Wear clothes that will emphasize your best parts and create the illusion of a very fit body.
Wear a good bra and underwear when you try clothes on.
Make sure the item fits well, is not too tight or loose and does not have any unsightly bulges.
Check the quality of clothes.
Make sure they don't stretch too much, and make sure the material is good quality.
Look after your clothes.
Read the labels so you know how to wash, dry and iron them.
Don't just follow fashions.
Choose clothes that will flatter your figure and suit you. Not all fashionable clothes were meant for everybody, so find the clothes that are right for you.
Wear boy-shorts underneath your pants to make you look thinner and not have those embarrassing 'underwear lumps'.