I've been planning meals for my family for a long time now. I've done it a few different ways till I found what works for us. I suggest you take tid bits and figure out what works for your family as well. I'm always interested to see how other families do things to save money and make the function of their home work.
We don't eat out much, only because at this stage of the game eating out with kids is stressful and not fun at all. So I'd rather eat at home and save the eating out for date nights. Eating at home and planning our meals is one of the biggest ways we save money.
Every two weeks I sit down with the grocery adds, my day planner, coupons and plan out our meals. There are staples that we always get (bread, milk, eggs, etc) and then there are those things that we get for our weekly meals.
I like to search blogs, cook books and other sites for meal inspiration. There are meals that we have often, and then I like to find two or three new ones to try from stuff I've found through blogs, cook books and other sites.
From there I do my grocery shopping. Using the ads I like to see what's on sale, I don't mind going to a few different stores to get the best deals. On average I save between $30-40 dollars on my grocery bill, Here's a few more tips to help save money on your grocery bill.
*Shop what's on sale- buy produce that's on sale that week. Plan your meals around a few staple items that are on sale. For example, if pasta sauce and garlic bread are on sale make one meal that will incorporate that. You get the idea.
*Use coupons on top of your sale items if you can- not in a crazy stock pile kinda way but in a way that combines sale items on top of coupons. This is the best way to maximize savings.
*Take advantage of BUY ONE, GET ONE sales- grocery stores in my area have these sales all the time and I'm sure if you do a little searching you'll find some in your area too. When they do I take advantage of them and plan my meals around them, and stock pile my freezer.