Sadly, a general resolution to "watch your calories" just doesn't do it.
In order to work, a weight-loss system has to remind you each day of where you're at (in perspective with where you've come from). Ultimately there's only two measurements that count: your weight and your body fat percentage. Measure those every day and you'll be much further on the way to weight loss than by calorie counting. Sure, being aware of your rough calorie intake is useful supporting data, but you need to measure the end result to get the "proper" feedback.
The end result of weight loss is not calorie intake, it's loss of weight. If you want to achieve that end result, you need to measure it. Sounds simple enough, no?
Also, the end result is fat loss, not weight. Which is why I think weight is not the best metric, but performance in physical tasks. (As most people can't get their bodyfat percentage checked regularly, and performing various physical tasks is what allows you to keep or increase muscle mass while losing body fat.)
Literally counting every calorie gets old quick, but I think everyone should be able to estimate their calorie intake. It doesn't take long to calibrate your own intuition; after a week of paying close attention, most people should be able to guess the calorie contents of a plate of food.