Use deodorants. Under normal circumstances most women hate sweat odor. Hate it.
I am not even talking about using perfumes. Perfumes can be used ADDITIONALLY. I am talking about non-smelling, which is more important than good-smelling.
And *cough* pick-up lines as “I am stinking. Please wash me!” are wrong.
Marginal note: You cannot worsen things by non-smelling, you can however worsen things by perfumes (if you use the same/similar perfume her former boy-friend used).