Don't ever approach two women in the same group. No woman wants to feel like second best. Refrain from approaching one after another in the same group. You look like a loser and a women may think you are desperate, like searching the harbor amid the storm. Even if you're in that situation, as far as possible don't to show it.
When you compliment a woman, make sure that it is a sincere compliment. There's nothing worse than someone who gives too much compliment. Every person has something great about them, notice that and compliment them genuinely.
Do not ever put your hands on a woman uninvited. Some women don't mind the touch-sensitive, but the others feel uncomfortable with it. Respect the person until you have the opportunity to know more about her. Touching can be a lovely flirty action, but must be limited to the arms or resting the hand just above the arms and NOT touching, until you know more. Test of personal space by moving closer, seeing the reaction and then move back a bit to remove the threat.
Respect yourself at any time. Women always fall for the little people who can not be reached. Do not grovel or act desperate. Think of yourself as a special and know that you deserve to get the best.