How do I tighten down tub faucets if the tile wont allow access?

I'm going to be tiling in the tub surround, and it's where the faucets will go for the tub. If I need to tighten down the faucet handles, in what order do I do that and the tiling? Because I wont be able to get my hand under there once the tiling is done, but the tiling has to go under before I tighten the faucet down.

Do I just tile that little area first and then tighten them down and then tile the rest?

The method of attaching the trim varies by manufacturer and model. Most of the trim is attached after the wall is finished. What model and brand are you trying to install?

If you are talking about the rough-in body of the valve, that must be anchored before the finished wall is up. Those typically have a guide to tell you the min/max of the finished wall so the trim will fit.

faucet

I have no idea what you are talking about. The valve is normally installed and fastened, then the tile is installed over it, and finally the handles are installed. I do not know what you mean about getting your hand behind/under the tile to do it.