There are numerous resources available on the internet, as apps, and as little pocket-sized books for counting calories. You can easily look up how many calories are in a food with these. I use a food scale and measuring cups to try not to eat servings that are larger than I realize, and this has also made estimating serving sizes easier with time. When I first weighed a chicken breast I had no idea it was two or three times more than I needed. Counting calories also saves me money because I don't need to spend as much money on meat as I used to.
My favourite resource for logging my daily calories is www.MyFitnessPal.com. You can easily use it on your computer or smartphone, though it does have more options on the computer version.
On your profile settings you tell it your age, height and weight, and it automatically sets your daily calories based on your weight loss goal. I like to find my BMR (which you can do on their site or search online for a calculator) and then get my sedentary metabolic rate from that, but that's not necessary if you don't want to. Then start logging!
This is what my breakfast looks like:
On the phone app it only shows calories, but you can still see the rest of the info for your day's food elsewhere on the app (The bottom portion on the screen is an ad, so it's free):
Both the website and app have a lot of features, and they can be really fun to play with. I like that you can customize your goal, which some other programs don't let you do. They have a huge database of foods you can search through and add to your diary as you log. You can also add foods to it, and these additions are available to other users so the database grows. You can save meals so that it is easy to log things you eat regularly - for example my morning smoothie has a lot of ingredients but I saved it as a meal so I only need a moment to log it. Also, if your phone has a camera you can use it as a barcode scanner for packaged foods and it will log that for you.
You can track your weight here, and it gives a graph of your progress. It also has a bar chart of your weekly calories, and a pie chart of daily and weekly macronutrient intake if you want to keep track of that.
There's many more features available, but those are the main ones that I use. Give it a try! It's very easy and kind of fun sometimes.