Keeping a record of what you eat every day is an excellent idea. Most of us have no idea the number of calories we consume. This is an excellent website for help with this:
CalorieKing - Diet and weight loss. Calorie Counter and more.
You simply have to burn more calories than you consume. And remember that the weight which you lose slowly is a lot less likely to come back. Make calorie counting and healthy eating a way of life for you, rather than a temporary diet. Good luck!