What should I be aware of as I prepare to replace my bathroom vanity with a wall mount sink?
There are three things you need to consider:


Support;
Support; and
Support!


You NEED to find solid framing, probably uprights studs. You need serious screws/lag bolts into those studs. The sink is sure to come with mounting instructions as to exactly how to attach, but framing is a key.  Masonry hanging may be possible, but you will need very deep, serious anchors.

Many wall mount sinks can also get some extra support in the form of slender metal legs that help lift up front lip. A pedestal sink is also very compact and adds a center support. Finally there are corner sinks that rely on support from two walls.

Obviously there are a few other things, once you have solved that.  Where do the supply lines come from? Where does the drain enter the wall/floor? You might avoid the skirt (if you want) if you can position the lines to make them appear symetrical, attractive, etc? What type of fittings do you think are acceptable to see (solid chrome or brass? braided flex? etc.).  If you are certain they will be hidden, less of an issue.

Oh, by the way, if you don't have good SUPPORT, the pipes will eventually leak.