I agree about planning ahead -- in my notebook I write out a plan the night before, on a big post-it that I stick under the next day's entry. Sometimes it is very exact; more often it is like a flow chart ~
this or
that, and then
this or
that. You can still make adjustments as you go, just try not to make them after you eat something else, because then you find out you already ate Dinner's calories.
Re: snacking, I actually converted most of my week's lunches to snacks. I pace it out by splitting the day's lunch calories into 2-4 different eating times. I get a lot of things to eat if I'm having a small dinner or if the things I choose that day are low enough. Today's split-up is half of a ham and asiago sandwich (215 cals) as well as a WW yogurt with ground flaxseed (130 cals). I really like this because it keeps me eating more often and helps for working out as well, because I always save a little something to eat right after working out.
Things I use to cobble together a lunch:
apple with 1/2 tbsp PB or 1 laughing cow wedge
banana with 1/2 tbsp PB
low cal soups
yogurt with flax
1/2 sandwiches
peach, plums, 1/2 avocado or other fruit
Trader Joe's lite cheddar string cheese
frozen things I can microwave like morningstar Italian sausages
small salads (1 tbsp dressing)
veggies such as roasted cauliflower