I live in a fairly humid area, the last time I did this I bought one (can't recall the brand) that had a mold inhibitor in it, it's worked great for seven years, maybe longer. You may not need that where you are, but if the room isn't well vented it's worth a thought, and I just mentioned it so you'd know it isn't junk.

I also laid some blue tape along the edges to ensure that I had a nice, crisp line. I'm not a neat freak at all, but I've never had good luck with this task and didn't want it to look...tragic.

Good luck with it.