If you act needy, people will run away from you. Establish good relations before you ask for donations or you’ll be denied.
You are not “hitting people up for money.” You are offering them a chance to be of service, to be part of a greater good. Ask previous donors what they received from giving and then offer that.
They don’t give if you don’t ask. It is usually a brief period when you can influence people. When that moment wanes, withdraw and wait. If you ask (but don’t push) people will be more willing to say YES to you.