1) Layout of the Bathroom
Make sure they is enough room between and among the various facilities in the bathroom - the tub, the shower, the toilet and the sink. Keep in mind a window is a good thing, and make sure that there is sufficient ventilation....
2) Shower Drain Position
Each shower stall has a very specific location for the drain in the shower base. YOU NEED TO KNOW THIS VERY PRECISE DIMENSION WHEN IN STALLING THE WASTE PLUMBING. get it wrong and the base of the shower just won't fit!
3) Insulating the Water Supply
If the shower will be in an exterior wall ensure there is plenty of insulation to keep the pipe warm in the wall... TIP: create a false wall in the inside of the normal and insulated wall to house the piping...
4) Installation of the Shower Stall
Each shower has unique installation process. For instance the base of the shower stall we installed was inset in to the drywall so the walls when installed overlap the lip on the base - to create a water seal.
Advice: Buy your shower stall before to install the plumbing, and read the instructions first!
Five More Tips for Installing a Shower - May 23, 2009
Installing a Shower: Part 1 - Oct 12, 2008
Plumbing Tip: Check twice, three times before soldering... - Oct 23, 2008