Whilst the shopping to a list and meal plan is the best way to save yourself money / time there is also another nifty tip that for me works well and go hand in hand with this process.
I have certain grocery items that are just in the pantry - as I am sure we all do - sauce, dressing, mayo, plain crackers, pappadums, curry powder etc
Rather than try and remember what you need each week / fortnight - attach a piece of paper to your fridge or your cupboard and when you run out of something whilst cooking write it down. Make the list a permanent fixture in your kitchen so this tiny tiny task also becomes a fixture..
you'll no longer have 3 bottles of tomato sauce and no BBQ. French dressing but not italian, curry powder but not mustard powder and all types of pasta instead of 5 packets of fettucine!!!