The other day, after a meal with a friend, we were still sitting, lazily gathering dishes and putting lids on things in preparation for cleaning up. I had used a spoon to get some salad dressing from the container and the spoon still had a glob of dressing on it. My friend put the spoon on her plate along with other silverware. I silently protested. That half teaspoon of dressing should have been put back in the container for use at another time. I'll know better next time and not allow her to waste it. I'll get a spatula and clean out the spoon myself.
Frugal is a state of mind. Most people go through life wasting a half teaspoon of dressing and never even noticing. How many half teaspoons until you've wasted an entire bottle of dressing? How many pennies until you've wasted a dollar, and how many dollars until you've wasted enough to... get out of debt, pay off the house, buy a new car...
There are bigger things you can do, of course, and they should be done. Don't buy more insurance than you need, don't pay high interest rates and so on... but the little things add up, too, and it's in the little things that we develop and exercise a state of mind that we can put on auto pilot to save the pennies and the dollars and the hundreds of dollars.
Can't beat that for an easy way to save.