I am trying a tip from Suze Orman. I used to shop once a week, and then go to the store occasionally for things I had forgotten. The once a week trip was a full cart and expensive.
She recommended giving up that practice and only going when you actually need something, and buying only those things. I am finding I spend about half as much for food and grocery items. She also said to use what you have in the cupboards and see how long you can go without shopping.
The store is very close, so gas use is minimal.