I'm in sales and have trained sales people. I can't get into specifics here, but the biggest points I can give you are:
1) be upfront, straightforward, and honest
2) Clearly state your reason for being there (at their doorstep)
3) Don't pressure anyone to buy - this triggers simple or complex reflex objections (defensiveness and will not help you get a sale at all).
4) Give them an "out", meaning a way to contact you if they choose to not make a decision or seem to be hesitant. If they are hesitant, say no, or aren't sure, just give them an email or phone number to contact you at "if they should decide to buy some at a later time". People don't like to be backed into a corner. And for real, you're going onto their territory and invading their space which is worse than them coming into a store. You can even drop the line "If you aren't sure, please feel free to tell me no. I'm not here to pressure you to buy. However if you change your mind, here's how you can contact me..."
5) Always ask them how their day is going- don't just open up your "sale" asking them to buy right away. Tell them what you have - again be upfront - and allow them to decide. Don't ask them "how much would you like to buy" if they haven't told you they want any.
6) Always thank them! Go back later and slip a hand written thank you letter in their mailbox with more contact info "if they decide they want to buy more in the future". That's called getting "repeat business". And "repeat and referral business" if they decide to tell someone else about your cookie dough/pastries.
7) Always remember - there's no need to be nervous. Sales isn't a predatory act, it's people helping people - AS LONG AS YOU AREN'T BEING DISHONEST OR MANIPULATIVE
8) Get this out of your mind: You aren't "selling" anything to people. You are offering something to them that they might enjoy, if they choose to buy it. It's not about you, it's about you offering them something they might enjoy plus get satisfaction in knowing they are helping your Irish Dance School out.
9) Even if they don't buy, thank them for their time: sometimes politeness sells. This also doesn't mean they won't change their mind. Afterall, you will be giving them the appropriate contact info if they choose to buy at a later time. Give them that option, please. You'll be surprised at how many people change their mind after thinking about it after you simply gave them all the information without pressure and were ok with them not buying.
10) The first thing that should probably come out of your mouth should be a very quick introduction all in one breath that is very to the point also telling them your first name - Hi my name is Dave and I'm going around the neighborhood letting people know that I'm selling cookie dough and pastries to raise funds for my Irish Dance School. (Hand them contact card). I know you're probably busy so here's my card. If you'd be interested at a later time in buying, please call (or email) me. Would you be interested in allowing me to show you what I'm selling OR would you prefer me to come back at a later time? Again, do not ask them to buy. If you have to ask them to buy, they aren't ready. People will tell you if they're interested through their body language and expressed interest in what you have to offer to them.
11) If they appear to be interested and you have showed them what you're offering (selling), drop the line "if you're feeling interested, I can take payment/orders today, however if not, I'd be more than happy to come back or discuss this later. Either way, it's not a big deal" (remember, the times a salesman sells the most are when he's trying to sell the least and not forcing the sales).
I'm a professional sales consultant, have read numerous books/publications on sales, and have trained sales people before.