If you have porcelain or ceramic tile in your shower you are probably hesitant to damage it any way while putting up a shower curtain rod, yet without a rod, you risk having a mini flood in your bathroom every time you bathe. So you can go the more expensive route and risk damaging your tile by installing a permanent rod, or you can go the cheaper and easier route by installing a tension rod, therefore not risking your tile in any way.
Clean the tile thoroughly, then discreetly mark where you wish to install the bar. Measure from the floor on both sides of the shower enclosure to ensure that the rod will be level, and then measure inward from the outer wall of the enclosure. For example, if you wish to mount the bar at 7' high and 6" from the outer edge of the enclosure, mark a spot on both sides of the enclosure at that point.
Mark the spots where the mounting bracket for the shower curtain rod will be affixed to the shower wall. Be precise with indicating the position of each screw-hole to be drilled.
Drill the holes for the mounting brackets. Use a variable-speed drill at 100 to 200 revolutions per minute, using a fresh diamond or carbide blade rated for boring into ceramic or porcelain. When drilling, do not apply too much pressure, and dip the drill bit into lubricating oil after every 30 seconds or so of use.
Screw the mounting brackets into place. Use the step stool to properly reach the height to reduce the risk of injury. If there is no stud to sink the screws into, consider using a plastic anchor to stabilize the screw and protect the tile.
Insert the shower curtain rod into both ends of the mounting brackets and tension the rod into position. Use the level, if desired, to ensure the placement of the rod.
Put the shower curtain with its liner on the shower-curtain rod, and test the rod a bit to ensure that it is tightly fitted in place.