How can I change my "nice guy" image?

What you want to do is learn the types of actions that might label you an Average Frustrated Chump (AFC). Then avoid doing those things. An example, don't bring a woman flowers if you're just asking her to coffee. Don't ask for her number before conveying personality and gaining rapport - in fact, don't ask for her number at all directly. Let her figure that out when you end a conversation and indicate you have somewhere else to be ("I enjoyed our conversation. I have to go now - what do you think we need to do in order to continue this at another time?"). If you've successfully attracted her, she'll whip out a paper/ pen because she'll WANT to give you her number. Don't compliment her excessively when first meeting her. Don't put her on a pedestal. Don't spend money or a lot of time on a particular woman unless she's already reciprocated your attempts at attention.