If I don't say so myself I make a damn good mac and cheese.

So good it needs to be protected most of the time. Just about everyone I have fed with mine says it's the best they have ever had.
First off, there are no rules. Put in the stuff you and your kids like eat.
My tips:
*Lots of caramelized onions. Cook them low and slow in animal fat for best results. It will be almost like onion jam if done right.
*Bacon is always good. Crisp up some lardons and use the fat for the onions. (Ham or some sort of smoked sausage will work too. Hempler's Andouille is divine.)
*1-1-1 for your base sauce. 1 Tablespoon of butter - 1 tablespoon of flour - 1 cup of half and half. Make it a pale roux low heat 3-4 minutes then add the liquid, make as much as you need to make the batch. 3 works good for a pound of pasta.
*Use good cheese, the kind you like to eat. Good cheese will let you use half a cup of shredded cheese to each 1-1-1 you used for the sauce. Then top with more shredded cheese use the amount that looks right to you before bake.
*Cook the pasta for 75% of the package al-dente cook time.
*Use a shallower baking dish, it makes more surface area and that gives more nice crunchy bits after baking. 375F for about 30 minutes is usually good enough. Sometimes it takes a bit longer or not as long.
Hope that helps a little.