Couple of thoughts:
-I don't know what kind of chocolate you are eating, but if it is just milk chocolate, you might try darker chocolates. They are usually lower in sugars, better for you (as far as chocolate goes), and for me, I tend to savor and enjoy it more slowly. Explore new flavors, and try to be more mindful of the chocolate versus just satisfying a sweet tooth.
-When you mention slowing down your eating, that is a definite plus. I have read it takes quite awhile for your stomach to register it is full and relay the message of fullness in a physical response. Try counting your chews of your food, and try to extend it to 10 or 15 chews per bite.....this creates better digestion on top of helping you read when you are truly full before you over do it.
Try to explore the flavors of the food you are eating while you are consuming it. Taste the spices and the components, consider the ingredients and try to mentally find the taste of each one. This might seem crazy, but the more mindful you become of what you eat, the more likely you will make healthier choices. Its a habit, just practice it as often as you remember, and over time you will start to do it second nature.
Awareness is a huge step.....best of luck on your challenge!!