Well, the ceiling mount is the toughest one to do right. It still isn't bad, but I would consider a couple of things.
First, how big is the room? If it is 20' or less deep, you might want to consider shelf mounting on the back wall. It is easier, and has the advantage that the projector doesn't drop down into where it might get bumped around. Which leads to...
Second, how high are the ceilings. It simply isn't going to work if you are planning on hanging it from a 7' ceiling above a 12" riser. Basically, make sure the projector isn't going to interfere with traffic patterns or sight lines.
If the ceiling doesn't have drywall yet, preplan for the cable runs. You will need power and a low voltage box near the projector for data lines. You will need to run an HDMI cable over to your equipment, so either pre-wire, or consider the joist runs carefully. You will also need to run low valtage wiring to the screen to handle the auto-retract feature.
Also, buy a GOOD mount, like a chief. The cheap mounts won't stay in place and will wiggle any time anyone moves. Trust me on this one, or you can buy my cheap mount...very cheap!