I have kept numerous food/exercise journals throughout the years and have always found them to be helpful. You can buy one like this one from GNC or make your own. You can jot things down on your calendar, on a sheet of paper or notebook in the kitchen, on a site like DailyPlate or on a paper towel. It's completely up to you. The point is to recognize how many calories you are putting into your body vs how many are going out. Depending on what else you are recording, you might even discover how much protein/carb/fat you are ingesting on a daily basis and can make adjustments as needed.
Like I mentioned, there are many ways of journaling. For the purpose of this blog post, I will share with you the way that I count my calories. It might seem too detailed for some of you, but it has worked for me. Insanity, as I am sure you've heard is doing the same thing over and over again, expecting different results. Well, on the contrast, if you find something that works, you should stick with it.
On my fridge, I have this calendar:
Once you have done this for awhile, you may be able to stop journaling and keep track mentally, but I have found that if *I* steer from this method, I gain weight almost instantly. Everyone is different though. I would suggest committing yourself to just one week of journaling to see how it works for you. Don't let insanity keep you from your dream...