There is a hefty amount of advice on the web for animation demo reels. Here are two well known sources- most animators have frequented these lists of tips:

http://www.carlosbaena.com/resource/anim_DemoReels.html

http://splinedoctors.com/2009/08/more-on-demo-reels/

The guidelines above are fantastic! But many animators only relate them to demo reels. The people that write these guidelines are entertainers, and much of their advice is applicable to films, shots or any creative endeavor.

For instance,  few would willingly announce their reel is 45 minutes long. Quite clearly, a 45 minute demo reel would have to be UNBELIEVABLY entertaining for an employer to even press play. Most likely, a reel labeled "a whole 45 minutes of animation" would be tossed in the garbage before being viewed. And yet, it seems a common habit for people to advertise their personal films by the length.

If you have browsed the internet's offerings of animated shorts- both good and bad- you've probably come across headings like this:

"Watch my film, it is a whole 20 minutes of animation and I did it allbymyself! I worked on it for 4 years."

Maybe because animation is so technically laborious, animators like to announce the validity of their work in terms of its difficulty. As if they are announcing to the world: "Hey! it was actually really hard to make such a long movie, so the least you could do is watch it!".

There appears to be a notion that spending more time/effort on a film results in a longer film. In a very basic sense, that is correct. But once the film reaches a professional level, a significant amount of time must be spent making it shorter- just like a demo reel.

Which is why I suggest the the demo reel tips.

Like a demo reel, a film is stronger when trimmed down to the best and most necessary shots. Both a good film and a good demo reel will hook you at the start, and finish with something memorable. Personality, unique characters, lack of distractions... all good advice for a demo reel AND an animated film.

This is not to say there are no differences between reels and films, but much of the core advice is sound. Your film audience is not so different from the animation recruiter that must sit and watch reels all day. We are all people with too much to see and do. Anything from a silly joke to news of genocide across the world is fighting for our attention every minute. Consequently, a joke that boasts ten minutes of set-up better make us pee ourselves laughing- or else the joke needs to be much, much shorter.

Imagine an animation prompted by a quotation reminiscent of Blaise Pascal (I've also heard it attributed to Mark Twain).

"I apologize for the length of this film, as I did not have time to make it shorter."

-Tom