How do you plan groceries/meal plan for the week?

On Sundays I pull out my cookbooks and plan my dinners for the week, making a note of the ingredients that I need to buy. I'll also check for anything in the pantry or fridge that I'm running low on and want to replace. Then I'll take my list and go shopping Sunday evening.

Planning my meals in advance lets me plan to use up anything I might have (if I'm making a meal that uses some spinach, I can plan another recipe with spinach later in the week so I use it all).

I mostly use the subscription service Real Plans. I have a couple of add-ons from my favorite cookbook authors, and I have some flexibility to add in other recipes that I want to try. My favorite part of the Real Plans site is that once you've selected your recipes for the week, it makes your shopping list for you. I do try to stick to items that are in season to keep costs down, and always throw in a soup recipe to make sure I have a quick/easy veggie source throughout the week.

I sit down and write a list of 28 dinners that I divide into 4 groups of 7.
Sometimes I will have themes in mind so I just have to choose 4 of that type of thing and plug it into each week. So one night each week is pasta and another is soup for example.
If we are having a pork roast I have planned how I will use the leftover meat another day. Same with something like cabbage where I might not use all of it in one meal.
I post my meal list in my kitchen. I choose what I will have each day and cross things off as I have them.
I don't generally plan breakfast, lunches or snacks because I eat a limited amount of items for those and just have to keep stocked up.

I have a paper list in my kitchen that I add things to as we run out and a grocery list saved on my computer that I update. I buy some things every single week like fruit, milk or peppers. I look at my meal plan and add what I need to the grocery list once a week and then shop.

I do look at store ads or sales but it doesn't impact my shopping much. I might buy 2 packages of chicken when they are on sale because we use chicken a lot but I'm not going to buy something just because it is on sale and then try to figure out how to use it.
I do try to stick closely to my list while shopping. I do require that my family and myself think about what we want that week before we shop. If they want chips they had better get it on the list by shopping day.

I get my meat from a local farm and butcher box. On Thursdays I look through the freezer and see what meat I feel like eating and decide the preparation. On Saturdays, I go the the store to get all the things I need, usually just vegetables. Since I don't buy my meat at the grocery store, sales don't mean too much to me. I just buy seasonal produce, better quality, better price.

I buy around protein. I try to eat grass fed no-hormone meat which is expensive, so I buy whatever is on sale on the weekend and focus around that.

Many times I have staples in the house, so with the protein, I can change the sides up by simply buying some fresh produce (if needed). I also try to repurpose everything...if I roast a chicken, I try to make different things with it so i don't get bored (soup, empanadas, hash, etc.).

I scout recipes pretty much every day (I read Buzzfeed, the NY Times cooking section, etc. every morning) and bookmark any that look good by month and year (so if something looks good but is out of season I bookmark it in the appropriate upcoming month). On Tuesday or Wednesday I go through this month's bookmarks and choose 3-5 recipes that look good, depending on the quantities of each, and create my shopping list from those recipes. After that it's just a matter of rounding out the list with breakfast and lunch stuff!

At the end of each season I archive bookmarks -- I just move, say, September, October, and November 2017 into a group titled "Autumn 2017" in case I want to revisit any recipes. Some months I add a sub-folder (like in November 2017 I had a sub-folder for Thanksgiving recipes). It all sounds ridiculous when I type it out, but the key points are 1) regularly scouting/saving recipes, 2) making a realistic weekly plan from them, and 3) creating a shopping list directly from said recipes so nothing is overlooked.

I buy in bulk and stock up and, except for fresh fruit and veggies, have enough food in the frig/freezer and pantry to last me for months. So, I usually just eat/cook what I want each day with what's on hand.

I start w/logging breakfast and then plan lunch and dinner as necessary to meet my cal/macro goals by pre-logging those meals based on what I feel like eating/cooking

If I want to eat/cook something but find that I don't have all the ingredients on hand to cook it, I put the ingredients that I need on my grocery list and delay cooking that dish until I buy what I need to make it.

I usually hit the supermarket or grocery store 1x a week to buy fruit and veggies. Usually know exactly what I need/want and spend very little time wandering the aisles. I only wander thru the meat/poultry/seafood depts to look for bulk deals there.

We make a shopping list every Saturday...most items on that list are staple items that we can use in a variety of recipes...we pretty much go through the pantry, fridge, and freezer and determine what staple items we are out of or running low on and add them to the list.

Beyond that, we go through what recipes we're going to make during the week and figure out if there are any ingredients that we need that may not be staple items and we add those to the list. Usually while we're shopping we will come across something that sounds good that wasn't on the list...like last weekend we were shopping and came across a package of vacuum packed beets that were already roasted and peeled...we love beets, so we through them in the cart.

We usually shop on Sunday morning.

OP, you don't mention how many are eating in your household. More people means more food (and if they are teenagers, more uncertainty), but it also can mean more help. I don't shop without a list. Candidly, I rather dislike shopping and a list helps me get it done fast. Wandering the aisles and making it up on the fly makes me crazy!

Pantry items: There's a running list in the kitchen that everyone contributes to. If you use the last of something (butter, laundry detergent, whatever), you better put it on the list or I will get after you when we run out.

Breakfasts, lunches, snacks: Everyone has their own regulars (rotation of 3-4 things) for breakfast & lunch (only one kid makes her lunch for school). I stock what is requested. If it's not on the list, it doesn't get purchased.

Dinners: I do plan these for the week based on how who is expected each night. With teenagers, things change, so I stay flexible and can easily swap the meals planned on different nights, but having a basic plan from which to improvise ensures we have enough to feed everyone (including unexpected friends now and then).

It also helps to cook meats in quantities that can be used for several subsequent meals. E.g. we smoke a chicken every week. Chicken leftovers can make literally dozens of other dishes. Very versatile and cost effective. If chicken breasts are on sale, I buy a bunch -- enough to eat a couple dishes that week and freeze some for emergencies. Pounding them to an even thickness and wrapping individually helps them defrost & cook evenly. Pulled pork shoulder, pork loin, beef -- they all can be used in a huge variety of ways to avoid leftover monotony. Sea food is the only thing I cook in the quantity we plan to eat that night.

I group text the family on Thursday for their best guess on who will be eating what nights and plan what people like for the nights they will be there. I check sales online (especially meat), plan Thursday and shop Friday. That gives me the most flexibility on weekends when we need it the most. It also means we're doing more cooking on the weekend & using time-saving leftovers during the week.

Sitting with a cup of coffee and making a plan (and list based on the plan) is worth the few minutes it takes once a week. Good luck, OP!

Sunday me and my bf mealprep for the week and we both eat the exact same thing for lunch every day because we really don't mind. I make 2.7kg ground beef into a thick ragu, we boil potatoes and package that up for about 25$/week lunches. Dinners I do whatever because I just got an Instant Pot and everything is super fast anyhow haha

I don't buy my groceries (live with my parents) so I tend to have to try and convince them to buy healthy things like fruits and veggies when they go shopping and then I usually plan my entire day's meals the night before. I'm slowly getting them to buy healthier options so my choice of food expands.

Generally speaking, planning a week (or two if that's easier) in advanced is the best way to go and then only buying the foods you need, except for certain staples like milk, eggs, etc that you know you will eat and last longer than a week.