When it comes to food, the more you see the more you eat! Try not to fill your plate with food, eat slowly, and then go for seconds if you're still hungry. Chances are your first serving will be enough to satisfy your appetite and you won't need to go for more.
If you're eating out, ask your waiter to pack up half your order to go and only serve you the other half. I bet you'll be amazed at how filling the half portion is and you'll leave wondering how you were ever able to eat the full meal before. More often than not, the serving sizes at restaurants are double what you should really be getting anyway. This really works- I do it all the time!!