V.W.
You can go online and read about the proper care for marble. Has it been sealed? Or you could go into a countertop/cabinet store and ask them what they recommend for care.
We have granite... and while it is very hard and easy to "use"... it does require cleaning with more than hot water. :) Some of the sprays and cleaner/polishers out there work better than others. You may have to try a few to see which ones you like best. I buy mine at Lowe's or Home Depot.
As for foods to watch out for... just be careful of anything acidic. Tomatoes (or tomato based sauces that might get spilled) immediately come to mind. They won't hurt it just to have it there while slicing, but you need to clean it up properly immediately afterward or it can etch/damage from the acids if it gets left too long (don't let hubby clean up the kitchen, lol).
http://www.life123.com/home-garden/building-renovations/c...