The purpose is to reinforce the combination. I mean, both beer and food dish must improve. Here you can find some basic rules.
* First choose your food-dish and then choose a beer, that goes well with your dish. Your waiter should be able to give you plenty of advise. Test him or her and ask which beer you should drink with your dish. The food and the beer must have the same taste-intensity. Take a light tasting beer with a light dish and, take a tastier beer with a spicier dish.

* Strive for harmony between sour, sweet and bitter in dish and beer. Repeat the same taste in dish or sauce, by choosing a beer with a similar taste-pallet. As an experienced beer-lover you can also experiment with contrasts.

* Choose a simple tasting beer, one clear taste, with a complex tasting food-dish. Different combinations are here possible. As a Maitre D or waiter, your recommendation will be appreciated and rewarded. Here is an opportunity to relate with the customer and show your guest your knowledge.