I've been menu planning for a number of years, and it's a great way of controlling the grocery budget.
Many blogs I read post menu plans for the week on Mondays, and it's a good source of tested recipes, rather than something someone's pinned thinking 'ooh that looks interesting' and not tried it.
Planning for me happens generally on a Thursday, to run Friday to Thursday. This helps finalise my shopping list for the week. I build my list during the week as items run out, add what I need for the menu and do my weekly shop on Fridays.
One thing I make use of is my big freezer. It's one of the first things I bought when I moved in. I grab meat in bulk or when on sale (or even better - both!) and freeze up into meal portions. I also blanch and freeze excess veggies from the garden.
This week's plan - 23 to 29 August:
Friday: The plan was for a beef curry, however once made (from a packet spice mix) this was too hot for J, so that got passed on to the parents, while we added toppings to a frozen pizza kept for just these occasions.
Saturday: Was going to be soup from the freezer, but I used the rice I'd cooked for the curry and made a fried rice with bits and pieces in the fridge/freezer.
Sunday: A pasta with a rose chicken sauce with mushrooms and spinach from the garden. The chicken used was left-over shredded chicken in the freezer.
Monday: Tonight will be yiros using left-over roast lamb.
Tuesday: This is family dinner night at the 'rents with my sister and her little boy.
Wednesday: Roast lamb rack with veggies. I managed to pick up a few mini racks that were just enough for J and I on sale, and put them aside in the freezer.
Thursday: Hunt the freezer night - I will often cook extra and put them aside for some nights. I then need to schedule freezer nights. If it gets too out of hand, it's freezer weeks to ensure turn-over.
I'll sometimes juggle when things don't go to plan - such as passing on the curry. The pasta and yiros were meant to be on opposite nights, but I swapped them over based on how the day panned out (Read: I forgot to get the meat out the freezer early enough...). But the menu for the week basically is as planned.