When on any diet, calorie counting is the best way to ensure success. While some plans will tell you that you do not need to, at the end of the day whether or not you are going to lose weight depends on if you have burned off more energy than you've taken in. By counting calories you can be much more sure that you are tipping the scales in your favour.
Calorie counting really does not need to be all that difficult or time consuming however. There are plenty of guides available now, online and in print, that you can purchase that will tell you the energy value of a variety of foods.
Furthermore, the more similar meals you consume while on your diet, the easier this process will be since you'll already know what's in it. If you don't need a lot of variety in your diet, it could be as simple as coming up with two or three days worth of menus that fill a certain energy allotment value (one specified to produce weight loss for you) and then alternating between these three menu choices. This will help to take all the guesswork out of dieting and make sure you see the results you desire.
Keep in mind too that even if you go over how many you were supposed to eat on one day, you can make up for this by eating slightly fewer the next day. It is the long term totals that are going to play the more significant role here.