How do I clean sperry topside suede shoes? They are my 4 years old so they will need to be cleaned often.?

I pretreated them with a leather and suede protectant spray but they already (in the 2 weeks we've had them) gotten a few spots. I know they wont be perfect always since they are a young childs but I'd like to try to keep them somewhat presentable for at least a couple months.