First of all decide the occasion ,is it something formal or casual, mostly if you have to go for formal occasion like wedding or something then go for a suit, black will look good or navy blue, if not ,a party or get together then go for a good shirt with a good pair of pants ,if you have to go for a picnic or something then go for T-Shirt with a pair of jeans or shorts ,and if you want to impress a female friend then take a advice from a female friend as if she likes it then probably every female will like it.