Really, there is no single correct way to proceed with fundraiser planning - you just need to use a little common sense. There are a lot of ideas out there that can work well for you, as long as you keep a few things in mind while you are in the planning stages with cancer fundraiser activities. The size of your group is important, as is the amount you want to raise. If you're managing a small group, then you'll want to go with cancer fundraiser products that have high profits, and you'll want to steer clear of a cancer fundraiser where the minimums are higher than you're comfortable with, or where the shipping charges would cut into your profits significantly.
You also need to keep in mind what your intended customer base will be when you are organizing a fundraiser. If you have been thinking doing something with cancer fundraiser candy bars, for example, that sort of idea will work really well with a younger customer base where a lot of your supporters either have families, or are younger people themselves. If your customers will be older people, however, you'd probably be better off with cancer fundraiser activities like magazine drives, or maybe something like scratch cards.