So, I've decided that I am too much of a pushover when it comes to satisfying Elsa and Clio's every whim. Or, perhaps more accurately, that they're old enough to start understanding that they can't have every little thing they want, whenever they want it. (And by "thing" and "whim," please understand, I am primarily speaking of graham crackers.)
Seriously, if given the choice, the girls would carb-load non-stop from 3pm until dinner time. (And then throw their dinner on the floor.) It's not like I've been completely lax in the past, but I've been inconsistent -- often saying no, no, no and then eventually giving in when I get sick of the whining and fussing. Really, it's not behavior you want to be modeling for your daughters.

"Cracky?"
This past week, I've started putting my foot down more. If they want a snack, I give them (for example) a graham cracker each (well, half of one), then another when they ask for more -- which sounds like "mo? mo?" followed by a sort of wincing / moaning sound if I don't put another cracker into their hands within .08 seconds -- but if they want thirds, I say no. Very firmly. "No. That's all. Snack is over. We'll eat again at dinner."
I'm also trying to get in the habit of setting up expectations, so the rules are clear to them (and me) from the beginning. I make a little speech like, "OK, we're going to have two graham crackers, and then we're going to put them away. Twoooo graham crackers." And then I might make up some goofy little "two graham crackers" song, like "Where it's at! I got two graham crackers and a microphone...."
Does it work? Well, I can't say it's been exactly painless. There has been much whining and moaning. It's tough to stick to my guns (OK, maybe two and a HALF graham crackers...but only cuz I like your face...) Sometimes I end up having to appease them with cups of crushed ice. But I find that if I do a double-maneuver of firmly putting the crackers away and then, Poppins-like, telling the girls what we're going to do next, they are fairly easily placated: "OK, the crackers are going bye bye. Now, let's go read some books. Into the living room we go. Spit spot!"
It takes a good deal of energy and resolve on my part, which is not always easy to muster, especially, for example, at 4:30 in the afternoon when you've been stuck in the house for the past three and a half hours trying to keep your children entertained while waiting for the cable guy who doesn't show up until an hour after the outermost range of his scheduled appointment window only to tell you your receiver is "sick" (huh?) and there's nothing he can do. But I digress.
I'm also trying to be firmer -- or at least more explanatory -- when it comes to things like picking the girls up. Or not picking them up, more accurately. I'm more inclined lately to say things like, "Mommy can't pick you up right now, she's busy washing dishes. I'll pick you up when I'm done, but you have to wait." Again, it doesn't always work, but I feel like it can't be a bad thing that I'm talking to them more like they're "big kids" and trying to set firmer limits. It's partly me -- maybe I feel more confident in my parenting lately, or maybe I just realize that I'm in for a lifetime of pain if I get in the habit of folding every time they ask for something.
I also feel like they're more ready for it. They may not be talking a whole lot, but they understand plenty. Probably more than I even realize. And I get the feeling that the more they exert their will and test limits the more they probably also need (and actually want, even if they don't know it) limits to be set. I'm not sure if I read this somewhere or it's my own crackpot pscyhological theory, but that's my story and I'm sticking to it. Really.
Where it's at!