Fundraising booths are often overlooked as possibilities for a school fundraising event. Especially if your event is outdoors (but even if it's not), people will be mingling and wandering around, looking for things to do or see or eat. This is a grand opportunity for you to take advantage of supportive people who are there to help out the school with money. Get some booths set up with all kinds of small fundraisers, so that the supporters who came to spend money can do what they came to do.
As far as the focus goes of fundraising booths at your school fundraising event, you can do anything you want to, really - some schools have a few booths with food and drinks, with another section for more fun things like scratch cards. Scratch cards are particularly useful, because people can carry them around through the crowd, as well. You may even set up a table or two with catalogue fundraisers, so that people who want to stop and browse can feel free to do so.
As you can see, there's really no limit to the amount of things you can have going at your school fundraising event, and it certainly makes sense to maximize profits as much as you possible can. Every time the people attending your school fundraising event have a free moment, you want them to be spending that moment digging deep and helping the school reach its goals. People who attend a school fundraising event are already in the mindset to be helpful, so give them every opportunity to be just that!