The first steps I've already shared when I added a faux brick wall to my studio. The sheets go up fairly easily and really help you feel like you're making great progress. This particular wall took three sheets.
The next step is the caulking between the sheets to hide the seams, followed by lots of hand painting of the caulk lines and the bricks themselves to give them a more authentic look. Again, there are additional details on my first blog post.
To create the plaster for this wall, I used drywall joint compound. In doing research I've read that some folks use this, some use drywall mud and others use plaster. Since I had some leftover drywall joint compound from our basement project, I went with that. You put it on with a drywall knife.
It dries a little yellow, so I used a very broad paintbrush to paint white paint over the top. I used more of a whitewash technique by dipping my brush in paint and then water. The final step in the painting process was to whitewash some of the bricks beneath the "plaster" since in reality they would have been worn and weathered underneath the plaster.
Once it was all painted to my liking, I used sandpaper to smooth, and in some cases remove more plaster in places creating jagged edges and blank spaces for more of a worn look.