SNACK CONTROL

Independence
My kids are old enough to get their own snacks, but they rely on me not only to tell them what's available, but to prepare it for them.
Portion control
One reason I haven't encouraged them to serve themselves is that their ideas of portion size are wildly different. My son, who struggles with his weight, eats much larger portions than he needs to (biggest problem: breakfast cereal). My daughter, who has had growth problems in the past and needs more calories, ends up leaving most of her snack on the plate, wasting a lot of food.
Mindless snacking
If left to their own devices, they would snack all afternoon.
Cleanup
Lots of dirty dishes from all of the snacks.
Solution:

Portioning
I created single-serving snacks using Ziploc snack-size bags and Ball plastic freezer jars. I chose Ball jars because they're inexpensive, they're more compact and sturdy than other plasticware, they stack well, and they take up little space in the top rack of my dishwasher.
Into the Ziploc bags: chips, pretzels, crackers, cookies. I placed the savory snacks in a labeled "snack box" in my pantry, and the cookies went into the cookie jar (bonus: they stay fresher that way).
Into the jars: cereal, cut fresh vegies and fruit. Cereal goes into the pantry, vegies and fruit go into the fridge.
Labeling
The key to this system's success is the labeling. I use a Dymo LetraTag to make labels for EVERYTHING. In this case, I labeled the snack box with their snack allowance (two snacks per day, unlimited fresh fruit and vegies), and with ideas for other snacks that aren't portioned but that they can prepare themselves (pickles, string cheese, yogurt, toast with peanut butter and jelly, etc.).
I labeled the cereal shelf with a decent portion size: "Breakfast: 1-2 cereal cups"
I designated one of the bins in my fridge "Snack fruits and vegies."
Finally, I labeled an empty Ziploc bag carton as the holder for "used, clean empties" so we can reuse all the packaging. Most of the snacks are dry, so the bags can be used several times.
The beauty: grab-and-go convenience for me and the kids, the beginning of an education about mindful eating, and the confidence that comes from being able to help themselves.
It's great for me too -- while I'm not exactly a dieter, I do tend to eat without thinking. Having snacks portioned this way adds a level of consciousness to my between-meal grazing. And I'm saving money on my grocery bills -- snacks that used to disappear in days is lasting all week. Good all the way around!