"* Make full use of no hide terrain: Underwater, water and various other types of terrain are impossible to hide in. Utilize these terrain types for ranking on NPCs and try to think outside the box. Be sure to try to keep the 'detect invisibility' spell up as some assassins may use invisibility potions too and check the 'where' command a lot."

One would kind of have to play an assassin AND ranger to get to know the terrain types and how they affect hide/sneak. Is there a good reason only rangers can see the actual terrain type? Seems any ol' fool should be able to tell the difference between say, Mountains and Plains. Thiefs and Assassins especially could use the knowledge of the difference between hills and plains.