I'm pretty terrible at "planning" meals, especially since I'm still a newbie when it comes to actually cooking...budget-wise, it does help to plan ahead, so one can take advantage of sales (stocking up when things are less expensive, etc)
But how to actually DO it? I'm thinking of making a list of recipes and ideas, then combining them into a basic meal (meat-veggies-other) and writing these different combinations onto a 3x5 card. This way, the meal itself is already planned, it's just the order of the meal within the week that can be varied.
My ex used to do it this way:
Most breakfasts are cold cereal. On Saturday, she'd make bacon eggs hashbrowns; Sunday was waffles and sausage.
Sunday evening was a chicken dinner--either breasts, whole chicken, or parts, with sides etc.
Monday was leftover chicken (usually soup, which was always killed off that night--Yum!)
Tuesday was an "off" night, we fended for ourselves.
Wednesday was "creative" night, where she could try out a new recipe, or work on one that we liked that she hadn't quite mastered yet (it *always* tasted good, though! Really!)
Thursday was spaghetti, with sauce or butter/cheese and a veggie
Friday was pizza night. And beer. (Or other adult beverages)
Saturday was a salad dinner.
Most weeks were like this. After 23 years, it never got old.