Diet, My Old Friend
Kathy and I both agree that on those weeks when you just don't lose, it's time to bust out the measuring accoutrement. Measuring cups and measuring spoons are truly the dieter's best friends.
Sure, sure, after a while you get good enough to eyeball it. "Yeah, that looks like a couple tablespoons of salad dressing" or "this piece of chicken looks just about right", but you would be shocked how often you're wrong. When I hit a plateau or notice I've gained a pound or sometimes when I just feel like I'm not giving it my all, I measure.
And I measure and measure and measure. Coffee in the morning? Two tablespoons of Fat Free Coffeemate! And I actually use the measuring spoon. Lunch is a cup of broccoli and a piece of grilled chicken? I bring out my cups, throw in the broccoli and keep a deck of playing cards in my kitchen drawer to measure out my chicken.
Some people invest in a food scale, which I've been meaning to do, but never had the money for it, at least not a decent one. So I use all-purpose guidelines, like decks of cards, the palm of my hand, etc.
Next time you notice you're not losing on weigh-in day, try becoming a Measuring Spoon Nazi. You'll find that often the "Oh, it's close enough" mentality, will often show up right on your ass.