What's a good Science Fair Procedure?

What should my procedure for my Science Fair be? Serious answers, it's really hard.I can't think! Thank you?

• For my science fair project I have thought about it but it seems hard to do even though I wanna do it. My experiment will be on what household cleaners/disinfectants work the best. At first I thought about using a petri dish and putting disinfectant in it to see what kills more bacteria but then I would need an incubator so it would be like GROWING bacteria instead. So my science teacher said that instead of that I could get some dirt and put disinfectant on that and see how much dirt disintegrates but I didn't understand what he meant by that...and so I don't know HOW to do my procedure and WHAT to use and everything. I don't know the best way to do this experiment but it is too late to change it now and my teacher thinks its a good experiment. Please give me ideas! Thank you!

• Answer:

  go to the store and buy three different cleaners. then go home and collect samples f dirt. make sure each sample has the same amount or dirt. put the dirt in a cup and pour the same amount of eah leaner into that cupo. be sure to label the cups so you dont get them confused! after about 3 dyas, or maybe a week, take the same amount of dirt from each cup, and look at it under the microscope or whatever. whichever has less bacteria wins!!