Bring something that calms you down in the event of turbulence. I've been on a bazillion flights and still think the plane is going to fall out of the sky when there's even a little bit of turbulence. Familiar music, a passage from a book, or a stuffed animal all can make turbulence a little bit easier to deal with.
If you're doing a long haul flight, map out what you're going to do on said flight before hand and during the flight so it feels shorter. For example, on a 12 hour flight you can comfortably watch two movies and sleep for 8 hours. You could also sleep for six hours, read a book for a while and watch a movie. Or you could write your blog on the plane until your fingers feel like they are going to fall off, then sleep until landing. Whatever you end up doing, it will help you mentally deal with being stuck on a plane for the long haul.
What do you consider a long flight? I divide flight times into quick, short, medium, longish and long haul flights.
Short: 4 hours or less. Reading and munching, not too bad.
Medium: 6 hours. Enough time to nap, watch a movie and eat. Favourite length overall-- if I'm going to deal with two airports, I might as well be in the air for a while.
Longish: Under 12 hours. Depending on time of day, these are either sleep-the-whole-time or movie-binge flights.
Long haul: 12 hours and over. The longest flight I've ever been on was the 18-hour Singapore to Newark flight on Singapore Airlines. Great airlines, terribly long flight. Plan of attack-- sleep.