My only advice is don't do it in a rush.
I have mostly left these kinds of decisions up to DH. He came into our marriage, 32 years ago, with this kind of knowledge. Don't ask me how a 23 year old guy knew about picking tiles and window treatments. When we started the remodel on this house, I decided to be more participatory. I mean, DH and I have the same taste, but...
So we picked the cabinets, tile, etc for our kitchen and powder room, no issue. Those got done first by the contractor. DH did 2 other bathrooms on his own. Then, after about 8 weeks, they started on the master bath. Sometime in about the 4th week, we had to go and choose the master bathroom tile, granite and cabinets; this was a total reconfiguration/rebuild. It was after work and I was hungry, and the place was closing. We chose the tile, no problem, but I just couldn't decide on the cabinets and granite. So we told the guy, just choose the same as in the kitchen. Also, I was shown a plan for the bathroom, and said "fine," without really looking. I ended up with a ceiling to counter tall cabinet, that divides the double sinks in half.
I got used to that, but inevitably, everyone who sees this has the same reaction as me: that's weird. And having the same cabinets and granite as the kitchen is just boring. It's very high quality, but I wish I had chosen something different.
Next time, I'm going back to leaving it to DH. I just don't have patience for this stuff.