What makes a good short film?

I looked on several film sites as to what the factors are in making a good short film. I found these four useful tips on http://www.bbc.co.uk/filmnetwork/filmmaking/guide/introduction/what-makes-a-good-short
I think it is important to have an original and interesting idea and i found this tip useful as it advises me to look at recent newspapers and stories for inspiration.
When referring to the 'make it short' point our brief is to make a film no longer then 5 minutes from start to finish. The last point 'strong beginning' is something i hadn't thought about but now seems really clear that when writing the script for our film we need to catch our audiences attention straight way.