How can a "nice" guy be more like a bad boy?

If you can show a girl that you are a confident guy then that makes all the difference. Guys who seem insecure right from the start (like the first impression is that they are insecure) seem less attractive. If you know that you are a hot guy and know that you should be getting girls then that will attract us girls. Even if you are somewhat insecure about starting a relationship or nervous just try not to show that right from the start. That is something you can start to show as you get to know the girl and want to get to a deeper level with her.