Top ten things to know when writing a film

The website I found was by William C. Martell. He wrote the Screenwriting 101 column for the Independent Film Channel's magazine. The website is called Script Secrets-The Write Place for Screenwriting Information. He gives a list of top ten things someone should know if they are planning on writing their own film. They are:
1.“To write a good script that can be made cheap”
2.” You need a great high concept” or a great idea
3. To know what “you got access to”
4. “Limit and centralized locations”
5. “Limit your characters to 10-15 speaking roles”
6. “Nothing you can not control”
7. “One extra location”
8. “Stunts”
9. “If you are making an action movie or thriller, think personal” and
10. “Take things to the limit.”
He believes with having these things in your movie that it will turn out great.