Tips for Grocery shopping?

I am terrible with groceries. I go to the store to shop and i'll see something like french fries and i'll think i need it, and throw it into my cart. Then when I manage to get the energy to clean out the freezer, i'll need to throw out probably 5 bags covered in freezer burn. It's the same way with spices. I probably have three jars of smoked paprika because I can never remember what i have. Does anyone have any tips for this? I hate to waste food but i can't help it.