Serving basic food is pretty similar to serving drinks, except that you will more commonly need to carry additional dishes, rather than a single glass or mug.
As with anything, you must first determine what the person would like and how they wish it prepared.
Some examples... Meats - How well done should they be.
Vegetables - Steamed, boiled, roasted, sauteed, etc.
What sort of grains/starches do they want?
What about condiments? (remember, there are no prepackaged things like bottles of catsup and the like, no margarine, etc.. it is medieval times!)
If they are not extremely specific, use your imagination. "fresh seared steak with a huge baked potato and salad" is all fine and good, but that can get pretty boring if that is an all the time thing.
If you are bringing them just one dish of food, as a plate, or a bowl on a plate, then it can be served in the same fashion as a drink.
With more than one dish, bring all dishes on a tray and place them directly onto the table.
Always serve the dishes from the left and clear them to the right and NEVER reach across in front of someone!
Remember, quick, efficient and graceful are words to live by.