Wear clean, freshly laundered and ironed clothes that are free of stains, holes and tears.
This may sound like a no-brainer, but a lot of guys neglect to wash and iron their clothes, or continue to wear old t-shirts that have holes in them. Girls definitely notice such slovenly dressing, and it's a major turnoff.
Wear clothes that fit.
Jeans should fit snugly at the waist - not too baggy and not too tight. Pants and blazers should be tailored to fit at the waist and shoulders. Jacket arms should be an appropriate length - reaching the wrists when your arms are at your side. Likewise, pants should hit directly at your ankles when in your standing position. Girls are extremely impressed by men who recognize the importance of well-fitting clothes.
Wear clothes that match.
Don't combine different patterns and prints, like wearing a plaid shirt with striped pants. Keep your look simple, but stylish. For example, pair printed shirts with solid colored pants or shorts. Alternatively, tame embellished or striped pants with a plain polo shirt. A stylishly simple outfit that is sure to get you noticed would be a nice pair of jeans, a crisp white t-shirt worn under a v-neck sweater or polo shirt with a new pair of sneakers or black loafers.
Wear appropriate shoes.
Don't wear sneakers with suits, or wear flip flops on a date (unless the date is at the beach). Girls pay particular attention to a guy's shoes, and they can be extremely picky. Always wear black dress shoes and black socks with a suit or dress pants. Wear clean sneakers and white socks with jeans and shorts.
Keep jewelry and other accessories to a minimum.
Limit jewelry to one nice watch, a ring or a silver chain necklace. Don't go overboard with multiple rings, necklaces and bracelets. You can also accessorize your look with hats, scarves and belts.