The Hard Part
The hard part is learning a new way to consider food (calories) and then using that knowledge to change what you eat.
Counting calories is absolutely essential. It is one of those things that at the start is hard, that quickly gets easier and finally becomes so natural that you can do it in you head with no effort at all.
In order to count calories you have to control portions or servings. For example, I bought Corn Flakes, the nutrition label said 100 calories per serving and the serving size was 3/4 of a cup. So I actually went and measured it out with a measuring jug. Now I know for that particular cereal bowl exactly what 3/4 of a cup of dry cereal looks like. I did the same with the milk. Now when I count 180 calories for my breakfast cereal I know that it is reasonably accurate. You simply can't ignore serving size, do whatever you need to do to make sure you know what is going into your body. This might seem like dumb stuff to you, but I had never measured a cup of anything before. Didn't I mention I don't cook.
What did people do before the Internet? How did they live, hard to understand. Nowadays if you want to know how many calories something has just look it up online. I have found that CalorieKing.com is an excellent site for this purpose.
Of course there are times when you have to work out the calories in something from scratch. In that case just break it up into its ingredients, find the calories for each and add it up. You will do a lot of estimating of portions but I guarantee you will get better with practice.
Keep a record of everything you eat. Write it down. I use a spreadsheet (based on the one from Jeremy). Calculate how many calories you are eating every day. Don't worry about hitting an exact number. I take the average of the last 5 days and try and get that number to match my target. That way if I eat a couple of hundred too much one day I can eat a little less for the next 2 or 3 days and the average never gets too far away from the target.