Wallpaper help?

I've taken a break from the house this week. As you may have noticed. I did a big photo job during the week, and I caught up on some scrapbooking this weekend (I'm on the design team for Hambly Screen Prints).

In addition to a giant editing job I have coming up, I'm ready to get back to the house. The big project will be wallpapering the bathroom. I did this once before, in the condo where I lived before we bought this house. It wasn't terribly hard, just time-consuming. One error I made was to mark a plumb line with chalk. I ended up getting some chalk smear on the paper. This time I think I'll just use a level and draw the line on the wall. Remember, I'm only papering the upper half of the room, which is at most only four feet tall.

My paper is prepasted, so it should be easy, right? I already have a smoothing tool, and a large putty knife to use as a straight edge for trimming. I even have a friend who's willing to help. Am I forgetting anything? Let me know if you have any tips for making this job go quickly. I always appreciate your advice!