For a long time i used to be "that nice guy" because i used to give girls gifts. This is such a big mistake. Never EVER buy a girl drinks, flowers etc. if you never had sex with her (shel will take you for a sucker). If you had sex with her and you want to give something (let's say flowers) this is the way to do it.

In my personal opinion, if you want to give her something try to make it in a way that she feels important. If she is alone and you give her flowers then, she'll say "That's so NICE of YOU" so i've just become "the nice guy" that second and that's not good. Belive me, been there, done that.
If she is arround other girls (girlsfriends, girls from work etc.) that's the moment. All her girls arround her will envy her so she will feel more valuable. Girls arround her will notice your confidence and capability to provide, so those girls will be jealous on you girl and want you for themselfs. The moment you are desired by other woman in her group she will want you more (just like when you buy a new car and you want to brag)... by giving her a reason to brag with you, your value will rise, her friends will be jealous and she will compete with them for your affection, even more just to assure her place next to you.

I've tried this a few times and it worked like a charm.

Thank you!