Maybe, as its name implies, it would actually be easier to start with what it is not. 

It is not about patching special effects over a yawning hole of a story line; not about forking over $20 million for a brand-name star; not about an ear-splitting sound track that punctuates cartoon-ready dialog; not about an "idea" that's nothing more than a toxic waste dump of decaying cliches. 

In short, it is not about that great old Hollywood mainstay: 
Industrial Strength Film Making. 

Of course, the assembly line of Industrial Strength Film Making requires considerable sums of money.  And not to be facetious (well ... mostly not), it is in this respect that the micro-budget movie maker actually has an advantage.  Because such a movie maker literally cannot afford these industrial strength techniques. 

You think I jest?  Well, gentle reader, consider all the young film makers who started out with so much promise after making  their "breakthrough" movie - usually on a shoestring, a marvel held together with chewing gum and baling wire - but one which also had some kind of wonderful idea behind it.  And then consider what happened to so many after they came to Hollywood and the big time.  How the initial promise faded, and the new ideas disappeared, after Industrial Strength Film Making took over... 

Obviously, this doesn't always happen have to happen.  There are actually good people in Hollywood, many in the technical fields and trades.  And obviously, good movies are still made, from time to time.  But perhaps, when they are made, it is because those who make them have somehow managed to remain Unhollywood.  In some place close to their hearts.