I am a meal planner here too, I plan for a fortnight at a time because I hate shopping, and find it much easier to go and get it all done in one go (plus I also find it cheaper for some reason). What we do is start a shopping list the day we get home from shopping and just add things to it as we run out.
The day before shopping I sit down and thing of about 12 meals, some of them will be meals that I cook double batches and freeze half for work days on the following week. I also try to make sure we have a good balance of cheaper cuts of meat, mine, gravy beef for casseroles etc and more exspensive meat such a chicken steak etc.
Once I decide on meals I check the pantry to make sure I have all the other ingredients and if not add them to my list, along with any other pantry/ cleaning items we are getting a bit light on.
This week I shopped at coles online because I dont have the temptation of adding lots of extra things into the trolley as I walk down the isle, and I have worked a 4 day week- so not really alot of time to fit it in. I will go to the butchers to buy our meat (usually in bulk) and divide it up, and I will go to the markets on the weekend to pick up fruit and veg.