I started making a monthly menu when I got tired of eating the same thing week after week. I also found that as I was shopping I was buying more than I needed just to have things "on hand" which is really not necessary unless you live far out of town. As someone who doesn't live in town I have found that having one extra of things that I use most often us usually enough until I can get to the store again.
I started out by making a list of all the things that I cook on a regular basis, and things that I know the guys like to eat. I also made a list of things that I wanted to try out. From there I printed out a calendar off my computer and started to get things organized. For us I try to make a nice Sunday dinner, Monday night is pasta night, Tuesdays I make something that is easy to take to T-ball. Wednesday nights are taco night, Thursdays I try to make something new or just an old favorite. Friday night is pizza, and I get the night off on Saturday, so that means we go out.
We don't always stick to the menu, I use it as a guideline. Sure things come up and things get changed, but it is good to know what I am planning on making when I do my shopping each week. It has helped me to save money and that is what we are all looking to do these days. Give it a try, start out with a weekly menu and go from there.