OP, you haven't said if you cook. I'm going to assume that you have basic kitchen skills (ie can roast a chicken, do simple things without recipes, etc).
1. Think about the number of meals you actually need to plan for. Ie, the nanny doesn't eat breakfast, and DH eats lunch at work... etc. Many people plan breakfasts and lunches, I don't really (we always eat the exact same thing for breakfast, we're all out at lunch and I use lunch as leftover-eating-time).
So let's say you're planning to plan for 1 weekend breakfast, 5 lunches for nanny and DC, 4 weeknight dinners, and 1 weekend night dinner.
2. Fill in a couple things that you know you want/like/etc. Make sure you actually have time to make these things... ie not a super complicated dish for Wed night dinner.
So you might be here:
Sun breakfast: pancakes and bacon
lunches:
Mon dinner: spaghetti and meat sauce
Tues: grilled chicken breasts over pasta
Wed: nothing planned, you'll go out
Thurs:
Fri:
Sat dinner: steak, corn, and zucchini on the grill
3. Then start looking for opportunities to double up on / use up ingredients before they go bad.
Sun breakfast: pancakes and bacon
lunches: BLT's and/or leftover spaghetti
Mon dinner: spaghetti and meat sauce
Tues: grilled chicken breasts over pasta
Wed: nothing planned, you'll go out
Thurs: leftover grilled chicken in wrap sandwiches
Fri: salmon and sautéed veggies
Sat dinner: steak, corn, and (leftover sautéed veggies) on the grill
4. I generally do some adjusting... I only grocery shop 1x/week and prefer to eat any seafood within 24 hours of it hitting the fridge. Cook once, eat twice (see what I did with the chicken? Maybe chicken is on sale this week. Etc.
5. Keep a good pantry/fridge/freezer with YOUR family's staples, whatever they are, so that you can always throw together a quick weeknight meal or lunch of... something. I always have on hand: frozen edamame, frozen fruit, plain yogurt, crackers, pasta, canned diced tomatoes, rice, ground beef and usually blsl chicken thighs in the freezer, parmesan cheese, and eggs. I only meal-plan 4 dinners per week... the rest of the week, DH works late so I either use leftovers those nights or make something based on whatever's in the house at the moment. After a little while you'll figure out your own rhythm for how often to plan for leftovers, etc.
I'm not a huge sale-er and coupon-er, but I do take advantage of the fact that larger cuts or quantities of meat are often less expensive per unit. So If I'm grilling chicken breasts, you better believe I'm grilling a ton, and serving them in various ways all week. Or freezing some for later use.
a typical meal plan and shopping list for our family:
Sat grilled chicken, corn, and tomatoes
Sun tacos with leftover chicken, leftover corn, salsa, cheese, rice
Wed beef and broccoli stir fry with leftover rice
Thu roast beef sandwiches (roast the meat the night before and slice thin), salad, fruit
shopping list: fruit, corn, tomatoes, salad veg, broccoli - chicken, ribeye, roast - salsa, shredded cheese, eggs, fruit and cereal bars, bulk almonds and raisins