Mjasp,
You're right, the anchors on the carpet are blue when facing one way, or red when facing the other, but I can't remember which way is which. I know that this was helpful during my first cruise, as we headed the wrong way down the hall on occasion.
Another way to remember is that the forward and aft elevators face aft, while the midship elevators face forward. When you get off the elevator, take a second to figure out which way you want to go and which elevators you just used.
If all else fails, there are signs in the hallway outside of each elevator lobby which direct you forward or aft. I think I was on my third cruise before I noticed these!