We try to do what peanutter does. Plan 5-6 dinners and do the plan before you shop, so you can add the needed ingredients to your shopping list. Then a list goes on the fridge with each day and what we're having, so we can defrost meat etc.
I try to pick meals that take no more than 30 mins to cook for weeknights and leave the fancy stuff for the weekend. Also meals needing fresher ingredients eg salad, herbs etc I put at the start of the week (let's face it, lettuce bought Saturday may not last til Friday!).
I don't work on Monday so often will cook something for Tuesday night ahead of time on monday eg lasagna, pasta bake or a slow cooked 'thing'.
Having said all that, I've only resurrected this concept about 6 weeks ago and I am pretty sick of meal planning already ha! In a perfect world I would have a magical excel spreadsheet with a list of meals an ingredients