Oh wise wizard Bill, please enlighten us on how to cross the Dead Marshes, preferably without succumbing to a horrible, screaming death.

Don’t be in the film adaptation of the Dead Marshes.

On a serious note, so long as you do as Gollum says and never look in the water when you see the lights—which is an odd thing to say but is possibly one of the few times one can say it—you should be fine.

Unless, of course, you’re in the film adaptation. Then I am so very sorry.