Check with your council office, they will have kits for activities that you can check out, and ideas for service projects. The kids generally can come up with ideas for community service that are meaningful to them. Do the cookie sale tryit and do some of the council cookie events too, there should be a cookie rally.
I would suggest that you get the cooke training before you start thinking about orders. The initial order for cookies is based on what your girls presell, they go door to door, in school, to family and firends, and take cookie orders. You should always go with your daughter, and she should wear her uniform. We have a small liberal arts college here, and the dorm is a great place for preorders. Always go with your child. For the initial order, you will have to order in cases, so you need to round up, for most varieties, especially Thin mints and Samoas. If you are not going to have cookie booths, you round down, then pick up the extra boxes you need at the cookie cupboard so that you do not have any left over. If you are going to have booth sales, you use the cookies that your girls presold for the first weekend of booth sales, and then you restock at the cookie cupbords begining the monday after the first weekend (that is how it functions here) so that the girls can fill their presale orders. At that time, you can take out more cookies if you want to sell at more booths.
Check with your cookie booth coordinator about the numbers of cookies you can expect to sell at different locations, there should be a person in your service unit who is coordinating the cookie booth sale locations and times. That person will contact the businesses and make arriangments, you should not go out and do this on your own unless your service unit has told you to function in this way. We have had success at busy restaurant parking lots, gas staitions, drug stores, grocery stores and one of the very best is the library. You need permission (again, make sure that you follow the serivice units rules) and do not rule out the idea of being outside for your sale. The sidewalk from the library parking lot is a fabulous spot on weekends. If you work a grocery store, try to be at the exit instead of the entrance, people are more likely to stop then, they are focused on going into the store and would usually rather stop after.
Because they are Brownies, you should count on them not being able to work a cookie sale for more than an hour at a time. When they get a little older, they do better. You may want to have one girl leave as another comes in to work the sale, and having too many at the sale at one time, leads to horseplay instead of work, so I usually limit to two girls at a time. Count on Thin mints and Samoas outselling most other cookies by a considerable margin. Here, for a 4 hours sale, I will take 4 cs TM, 3 SAM, and 2 or 1 of most other varieties. The girls need to do the stocking, the selling, and the work. Parents are there to take money. Only adults sit at booth sales...I tell my girls that they are girl scout cookies, not woman scout cookies, and it is the death knell for any cookie booth to have a bunch of girls sitting around, and the adult jumping around holding the sign. Most people won't bother to buy if it appears that Mom is the one selling. Let them take ownership, it is more meaningful for them.
Some booths will be much better than others. You will find that you will have the best luck if you divide the booth sales by hour, instead of by who worked what sale. Keep track of the number of hours each child works a sale. Keep track of the number of cookies you sell at sales. You have 7 girls who each worked a different number of hours. You sold 500 boxes at the sales. You count up the number of hours the girls worked (say 40 hours combinded) then you divide 500 by 40 hours, and you have the number of boxes of cookies your girls sold per hour, then you multiply each girls hourly total by that number. I have done it both ways, and somtimes, a girl will work a booth where they sell 17 boxes, and right down the street, another girl will sell 100 boxes. It just makes it a total group effort, and every one is working hard and is not disapointed when they draw a dud booth. It also keeps the kids (and Moms) who are most aggressive from having a reason to hog the best spots. It happends...and I detest that, so any way that you can limit this, is good. They are earning money for the troop, and the trinkets they get are really not so important.
M.