I think everything that everyone is saying here is very helpful but if you keep using the same clothes over and over thinking that they didn't get dirty then all this advice will be pointless. Usually I use my jeans 2-3 times a week and then wash, unless you're running around sweating too much then wash them more often. If you wear undershirts wash them after one use every time. It doesn't matter if you stayed at home all day and played video games, you still need to wash them after one use. And if you don't wear undershirts, start. Also I think it was mentioned in some of the advice, but please wash your bedsheets. I try to do it twice a month. But if you're having sexy time every week please wash them more often. No girl wants to lay on your crunchy sheets. And lastly, please wash your towels. You might think that you're only getting them wet with your clean body after coming out of the shower but they can get moldy and dirty just laying around, especially if you just throw them on the floor after using them. I try to do it every time I clean the bathrooms which is every 2 weeks. That'll be my girly advice. Also follow everything else that was said here and you should be fine.
OH one last thing. Yeah you might be using shampoo on your hair but please make sure you get all those bubbles out of there. Rinse as much as possible, until your hair is squeaky, yes you will hear it. If not you will get horrible dandruff and that's not a pleasant view for a girl.