Ok, you know how I said you should track your spending? Well, when you are trying to tighten up your nutrition, you should track that too. I like to use just a paper journal, but there are a ton of food tracking apps out there. When choosing one, be careful that you are not giving it too much credit. There is NO WAY that an app that is used by millions can accurately tell you how many calories you are taking in and expending. These are ball park figures and you need to take them with a grain of salt. Each person is unique and I will absorb an apple differently than you will. The thing that you are looking for are trends or habits.
Write down what you are eating along with how you feel after. Be sure to track your caloric beverages as well. It can be very eye opening to see what you are actually consuming. If you are struggling in the gym or lacking energy, take a look at your journal and see where you can make some tweaks. There are a ton of nutrition coaches that can help and take a look at things for you.
Just like with finances, be sure that you are eating because you need to, not because you are bored and just want to. If you continually give in to the sweets, treats and little things that do not offer optimal nutrition, you will feel it and see it over time. Choose your foods with love for your health and wellbeing. Make your choices based on knowledge not of "feelings" so that you are fueling yourself effectively. You do not have to track forever, but I recommend getting a few weeks of data so that you can get a good picture of your habits.