In order to lose weight and keep it off, I find the following tools essential for success. I find daily weighing keeps me honest and on track. In addition, I find taking measurements periodically helpful as well. Finally, I weigh not only my body but my food as well. My first choice in measuring food is usually a food scale because it seems to be the most accurate.
A measuring tape is an inexpensive tool to track your progress. I take my measurements every few months to make sure things stay on track. Weight is an important measurement but taking individual measurements of arms, waist, thighs, etc. gives a more complete view of how your body is changing over time.