Hi, it's important to have some anti slip mats or stickers to ensure that you don't slip and lose your footing. Furthermore I think it is also imperative to have a grab bar or two placed into good spots so you have something to steady yourself with when you go into and out of the shower/tub. No one wants to slip. I just finished working on a bathroom reno and installed 2 grab bars. Make sure they are installed properly, like make sure they get screwed into the joists - otherwise they won't be any good.
Barring that - a cell phone within reach is never a bad idea.