I’m not going to tell you to turn your kitchen into the set of Breaking Bad, but a little measuring will keep you honest. Measure your proteins in ounces and your carbs in cups (most of your fat should come as part of your protein foods; add any other fats sparingly). You can use the palm of your hand to approximate three ounces of meat and your fist for a cup of rice or potatoes. The length of your thumb works well for measuring fats; it’s about the size of two tablespoons of oil or peanut butter.
This makes keeping a record of your food intake much easier, and eyeballed estimates will be close enough until you get very lean. At that point, you may want to invest in a food scale to make more precise measurements. The sharper your abs get, the more important the difference between one cup of rice and one half cup becomes.