I have four tips for happy dining at AN.
1. Avoid the restaurant cluster beside the TCC as much as you can. This is where the long line-ups are. Harvey's and Tim Horton's (the one right in the cluster, not the one near the Radisson - that one's actually not bad) are probably the worst contenders. Restaurants inside the Doubletree are also bad for this. Generally, the further away from the main convention area you are, the better off you will be.
2. Avoid eating at restaurants during key convention hours (unless you have a car, are willing to pay for bus/taxi fare, or are willing to walk for 20+ minutes to get to the not-as nearby restaurants). Have your own food and drinks handy for this time. Another thing I've done during this time period is ordered food by phone or Internet for pick-up.
3. Do research before you get to the con. Use googlemaps or something similar to look at all the options you have. There are all kinds of restaurants serving all kinds of food at all sorts of price ranges. If there are any particular places you want to eat at, get their phone number so you can phone before you go there (assuming you have some sort of mobile phone) to ask how long the wait will be.
4. Do not buy the food that is served either in the TCC or in the hallway of the Doubletree. Not only is it overpriced, but it tastes terrible, too!