make a list of the top 30 or so recipes you use most often; create a spreadsheet with the recipes along the side and the ingredients along the top; plan a week ahead for the recipes you want to make; circle ingredients on the spreadsheet, and you've got your shopping planned!
I laminated this to use week after week! It's perfect for us because we usually just plan suppers ahead (breakfast lunches = cereal leftovers). Some meal planner templates go too far and have a spot for every imaginable meal or snack. Helps me so much when I'm doing my weekly meal planning.