COUTING CALORIES

Good Morning everyone
i always read that counting calories is important and NECESSARY but i cant.
For me is imposible to calcolate the exact amout of calories per day.
For example if i eat some pieces of watermelons.....how can i know how many calories they have got ?
Sometimes i dont find the nutritive value on the food

How can i do ??

A food scale will help you to be accurate.

This isn't as hard as you think, but it does take some work to get used to weighing and measuring your food if you haven't done it. If you are eating watermelon, cut it into small chunks enough to fill a one cup measuring cup. Then to log it, click on "add food" under a meal or snack in your food diary, and type watermelon in the search box. Select the option on the right, in this case the first entry is raw watermelon, them on the left is the amount. Select 1 cup diced, and then add it to your diary. The work is done for you already as far as the nutritional information goes.