What changed how I cook is to look at recipies as guides. When cooking, I cut out all the oil.
I do the ziplock meats seperate thing, very handy.
When I cook, (it's just me) I make enough to last for a few days, but I serve it all into containers and portion it all out into equal sized before I take my first bite. When I am done eating, I know that the rest of what I made is already cool in the fridge and prevents me from taking seconds.