In a previous thread we debated how good, or bad, a DSLR was for video compared to other systems.
It occurred to me that, while shouting the pro DSLR video corner I don't use my camera as it came out of the box, when it is actually pretty poor for video.
I was therefore interested how you configure your DSLR for video work as such a beast is IMHO very different to the animal you use for still images.
To start the ball rolling:-
I believe an absolute must is a loupe. It gives a much better view of the screen, it is a third point of contact and (if you must hand hold) it puts the camera in the conventional place so you can point it naturally as you would an SLR.
With Loupes available at around £20 I would suggest this is the biggest assistance to DSLR video after the camera.