Any suggestions for installing new ceramic tile in a room that previously had carpet?

I'm installing ceramic in a 160 square foot sunroom that used to have a very short, cheap carpet. What kind of surface do I need to put the ceramic tile on? Any tips for starting / finishing the job and making it look nice?

Norm is right,backer board is specifically made as a sub-floor for ceramic tile.
HOME DEPOT carries two different types,Dura-rock which has been the the old stand bye for a number of years,and bye the sound of your project Dura-rock would work fine.
They also carry a product called Hardi-Backer which would be more applicable in a high moisture area(bathroom,kitchen)
Norm was also correct in addressing the prep work involved before installing your backer.
I like to screw the entire floor down before the backer goes down.It may sound like a lot of work but it's well worth your time.Remember you won't have a chance to do it later if a squeak develops down the road.
I like to screw the floor in a checkerboard pattern(6"or 8" squares)
Once the floor is ready just screw down your backer board using a similar checker board pattern.
Now your ready for tile.
Hope this helps.
Have A Great Day!

They sell a "backer board" that is specifically for that. You can get it at any home improvement center.

Before you do anything be sure to check the entire floor for squeaks or loose nails. Replace loose nails with screws. Now is your golden opportunity to have a solid floor.

There is a certain kind of board to use when installing tile. Home Depot offers a lot of free classes, including tile setting. You might want to sign up for one of those before attempting the job.

You must make sure that the floor is level. You can get self levelling concrete which is good. They say that when you lay tiles, you must make sure the first tile is laid exactly in the middle, this takes alot of measuring. Once you have found the centre square then you should start making your way to the back of the room (away from the door- this makes it easier for you to get out of the door if you have to). Get youself a good tile cutter and a tape measure and you should be fine. Also make sure you have the correct grout and adhesive before you start. Good luck