Portion control can make or break the efforts you've been putting in at the gym. Tools like a kitchen scale and measuring cups help you get a handle on portions by making sure you're not eating too much of a good thing.
I am fond of the all-purpose Tanita KD-400 compact scale ($60) because of its simplicity and ease of use. The Tanita measures food in pounds, ounces, and grams. For measuring cups, find a set from Tupperware ($18), which seems to be the most complete set of cups I have ever seen: 1/4, 1/3, 1/2, 2/3, 3/4, and 1 cup options.