My greatest contribution to the problem is refraining from raping women. My reasons for this are personal, but not complicated. Beyond that, I recognize rape as a very wide ranging definition, just as any general classification of crime has.
When we consider theft, there are many degrees of the crime, and the severity depends upon two things, the amount stolen and the violence involved. This is one of the strange things about the way we view crime. The threat of violence during the theft, compounds the crime, even if no actual violence of injury occurs. "Armed Robbery" is one of the most severe classes of theft. This is a kind of paradox because most armed robbers carry a gun in order to avoid violence during the crime. It's more efficient.
In the general sense, about the most any man can do to protect women from being raped, is set a good example. Part of this good example is to recognize the full length of the scale of rape, especially at the closer end. No one has trouble recognizing a crime as rape when a man breaks through a bedroom window and assaults a woman. It's less clear if he were allowed to enter by the front door. But, just as an armed robber does not have to actually shoot anyone, the threat of violence, not the actual injury defines the crime. This is true, however subtle the threat may be.