First of all, concentrate on getting it as clean as possible. There are many products on the market that will easily get rid of mildew. Lighten up the grout between the tiles. Get rid of soap scum. Make sure mirrors and the shower door glass sparkles.
Second, remove stuff from the counter tops.
Third, hide the plunger and trash cans.
Fourth, remove the rugs. They make a bathroom look smaller. Make sure the floor is clean.
Fifth, if you have a master bathroom, make it appear as an “oasis.” Place some candles around the soaking tub. A couple of plush towels. Maybe a fern or orchid plant.
The whole goal is to make the bathroom inviting and not have a buyer think they are walking into a locker room.