What are some key techniques for tiling a ceiling with 6" X 6" ceramic ceiling tile?
Do you do a couple tiles (4?) at a time and then put a piece of plywood up and wedge a 2x4, 2x2 up and let dry? 5.) Do you apply the thinset to the tile first then put on the ceiling?What type of thinset do you recommend for ceiling application?
What type of trowel do you recommend (U or V shaped)? How large should the teeth be?
How much thinset do you apply to the tile or backerboard?
How do you grout the ceiling and get the grout to stay up and not make a big mess all over the place?
What type of grout do you recommend?

Thanks for your help.

Lets first make sure you are using an acrylic modified thinset and not ordinary thinset which is used for concrete installation. Tell me about your backerboard please. Use a notched trowel and the size will be specified on the tub of modified thinset, probably 3/16". A notched trowel is neither U or V shaped, it is a notch with square corners. The tile will hold without bracing if you install correctly. For ceilings put the thinset on the tile covering 100% of the tile. As you set the tile give it a slight twist in one direction and then back. Check you spacing and/or install spacers and then tamp the tile with a rubber mallet.

Wouldn't it be a lot easier to just paint the ceiling in a high gloss latex? All that tile would make me dizzy.

The last one I did, I used a waterproof contact cement and glued the tiles to the drywall. The glue is more expensive that thinset, but it worked well. I installed 3-4 at a time and held them in place with 2x2's and small wood wedges. It took a while, but I would do those tile first thing and work on other parts of the project for a few hours to let the glue set. On one project, I ran everything from a center line and used rippers at both side walls. More work, but makes an awesome finished product.

I didn't know how to do it the way ballanger suggested. It would have been awesome not to have braced the tile!
Good luck with it

In post #2 I asked for more info on the backerboard. Drywall is not for bathrooms. The room needs greenboard, blueboard, paperless board or backer board. Contact cement may work but modified thinset is the appropriate installation. When folks are asking for advice I try to give them the info so they can make it a DIY project using the correct materials, just like the pros.