First thing first: you need the right numbers. For instance, “weight loss” is a silly path to sexy, sexy abs, since you’ll probably want to pack on heavy muscle while shedding those love handles. What you actually want is lean body mass.
Instead of a standard scale, splurge on one that measures fat percentage, such as the Withings Smart Body Analyzer. I’ve found that the Withings scale isn’t very accurate for measuring my total body fat percentages, but it’s generally good at measuring changes, which is really what counts in a resolution. Or, if money’s tight and you can dedicate more time, just pick up some skinfold calipers (a handheld clip).
In other words, you want a measure that is as close to your goal as possible. Instead of “going to the gym more,” try “increasing my max squat.” Instead of “walking more,” try “total number of hours active per day” (the Nike Fuelband SE has a nice metric for this one, since sitting all day can counteract scheduled exercise).
This makes nutritional goals difficult, because there’s no good way to measure whether your body is, in fact, absorbing them. Best to stick to performance-minded goals and see if eating healthier helps you meet them.