Any tips for door to door fundraising? Plz read all the detail its important?

Okay so I am helping out my friend Jasmine because she needs help fundraising door to door to get $210 total to go to Hershey park for a school music thing. So far we have made $80 but we would like to try to speed up our selling process. We are selling cookies, brownies,cofee, hot cocao, and tea. The cookies come as batter so you make them and the beverages come in packets and sort. We have been ignored many times after walking around for hours in the cold snowy weather. We live in a college town but we arent sure weather we should go to those houses? haha.What we have normally said is "Hi we are selling cookies and beverages to benefit us going to hershey park for a school music trip and we were wondering if you would be intrested.... If you have any suggestions on who to target, what to say, how to act...ect....ect. plz we need you help asap. Thankya so much. Buh bye.