All of the basic principles of photography and composition apply here.
A good macro lens is a nice thing to have when you're shooting food.
I usually use a combination of strobes, various light modifiers, natural light, and a ring flash, but a window will do just fine in a pinch.
With food you really need to pay attention to the presentation. Any decent chef's dish will display a balance of color, texture, shape, and ingredients. This balance is what you need to capture in your photo, and will determine the best angle to shoot the dish. Ask the chef why they plated the dish the way that they did, believe me, there is a lot that goes into a good plate design.
Once you have your angle figured out, you need to work out your background. The background should give context to the dish. Pick a setting that lends itself to the region, style, and season of the dish. If you can't get that setting, you might need to settle for a simple or solid background, but this will detract from the depth of your photo.
After you have your background figured out, then you just need to work out the lighting. This part takes a bit of practice, and I'm not sure what kind of equipment you have access to. If you camera has a built in flash, do not use it (ever).
Setting all of this up can take a bit of time, so you will want to do it long before the food comes out, I usually grab the same kind of plate that the food is going on, and make a rough mockup of the food with crumpled balls of paper. This way you can troubleshoot any unforseen problems.
Some foods will let you shoot for hours while maintaining their appearance, other foods demand that you get your shots quickly before they melt/wilt/dry out/separate/bleed etc...
Shiny foods look more appetizing. I like to keep a fine mist spray bottle with water, a container of canola oil and a paint brush on hand. Use the water for fruits and vegies, and the oil for meat and fish.
Have fun with it, and experiment.