I did this years ago but not too majorly and I definitely started getting noticed more by girls.
I always wear brand names because I'm a shallow tit with more money than sense, and it my style.
The first time i tried this was with a bright turquoise V-neck jumper (Lyle and Scott). I used to just wear like blacks, blues, grays n browns but as soon as I turned up to 6th form in that I had girls coming up to me saying 'You look very bright today!', 'I like your jumper!' randomly getting smiles and so on.
I think you do have to have the right body language when doing this though as you stand out more people will notice you, so if you carry yourself confidently you can pull off pretty much any color.
I'm not saying go out and but expensive clothes, what I would recommend is next time you go out try on colors that stand out and see how you feel in them. You will know what color feels right.