As it turns out, there isn't a particular "right" way to come up with good fundraising ideas for the ACS, because there are many fundraising activities that can work well. The way you have to look at things is by thinking about your fundraising team, and your monetary goals. Understanding your team and what you're aiming for will help you find the fundraising activity for the American Cancer Society will work best for you.
The size of your fundraising team has a lot to do with which fundraising ideas for you should consider first. If you've got quite a small group, you should probably be looking at fundraising products with low or no minimums, and high profit returns. Many direct sale fundraisers have free shipping, and for fundraising ideas like pizza fundraising cards, you can make profits of up to 90%. These can be fantastic fundraising ideas for if your team is not very big. If you do have a larger group, however, you may as well go for something like pretzels, which is a top selling item and only really works well as an American Cancer Society fundraising idea for fundraising teams that have a lot of people.