Research the organization making the grant
Just as different film festivals have different preferences, different grantmaking organizations have different missions. Do some research, and, if you’re lucky, you may find a perfect fit for your project. At the very least, you should avoid wasting time writing grants for organizations which will have no interest in your film. If the group specializes in experimental films, maybe you shouldn’t submit your Hollywood calling card.

 
Follow the guidelines
Read the grant application guidelines and give them exactly what they want, in the format and length requested. Don’t toss in extra material — a tired reader could easily get annoyed and toss out your whole application.

 
Be as straightforward and clear as possible
Murky, vague, pretentious writing will kill you. The reader making the first cut in the judging process is probably lying in bed the night before his or her deadline eagerly looking for an excuse not to finish reading your application. If you bore or confuse this person, you are lost. Be clear and concise.
 
Try, try again
If you don’t get it this year, apply next year for completion funding. And apply the year after that with your next project. I applied everywhere with “Fighting Grandpa” — I got almost nothing. But at least one of the organizations has subsequently given me money for “Brother Killer Wolf.” Even if you don’t get the grant this year, you may have made a good impression. Follow up on it!