If possible, try doing some gardening in the yard or at a local community spot. At work we're in a residential setting, and our current manager encouraged a few co-staffing and members to start up a garden. They've been able to plant strawberries, tomatoes, and potatoes in the past 2 years to help save on the grocery bill (meals for 7 - 8 people).
When running errands ... always keep a list handy at home or in the car. That way you ensure you are combining errands/tasks. Also, have an idea when and where you want to do your grocery shopping so that you don't find yourself short or feeling like you have to rush out to pick up only a few small items. General grocery lists really come in handy ... even if you know you're only looking to pick up 60 - 70% (or less) of the items jotted down.
Gas up during off-peak hours. I talked with a gas attendant at Esso years back and he noted it was frustrating the way the prices jumped around during the day, but often encouraged mid-week and to avoid the key times of the day (AM and supper hour). Aim to gas up really early in the AM, or late at night if at all possible.
Prepare meals wherein you're ensuring there will be possible leftovers. Soups, stews, and casseroles are great in that sense in that they're not usually "1-off meals" ... they tend to "have some life to them" (as the saying goes).