#1 I like soft chocolate chip cookies that are not flat. Adding a approx 1/2 cup of flour to a chocolate chip cookie recipe makes them soft and more of a mound than a flat disk. Bake a couple of trial cookies and if the texture isn't what you want, add a little more flour and bake a couple more til you get what you want.
#2 Cinnamon- oh it's so good. I never would of thought of adding this til I saw in it a recipe. I add about 1/2 tsp to 1 tsp of cinnamon. Gives the cookies a little more umph.