Anyone willing to help me with this?

Do you have any hobbies (cooking, drawing, photography, etc.)? Maybe you could do something related to that.

In some schools, doing a how-to on how to cast a spell may cause trouble with faculty and students, so be careful if you decide to do that. I like the dream catcher idea, personally.

My best how-to's were how to fold a guindaste and how-to care for a rabbit.

Your how-to should draw from what you know and are good at. Picking something that you have no or little experience in, may cause you to draw a blank or/and embarrass yourself in front of the class!

The magic tricks as long as feasible and not obnoxious should be OK! Magic tricks can be seen as old as they are done a lot and if you don't have a good one, people may believe it to be lame. I personally like the dreamcatcher one. So as long you know how to do it really well, you should be great.

Cooking tutorials are pretty common and any recipe works. Also, giving comida from the recipe to your class and teacher to try goes over pretty well! Hope this helps, best of luck!