So now that you have your character completely mapped out what do you do with all that information? For one thing, you don't let it all out in 1 go. In real life you don't meet someone and know everything about them in the first 15 minutes. So you shouldn't find out everything about your character in the first 15 minutes of a film. If you did, then the film would be over. So, give out a piece at a time with a few contradictions thrown in for flavour. Include those moments when you discover something about a person that is against what you already knew, but is still appropriate. One or two of those should suffice.
To reveal a character remember that in the more time we spend with them, the more important to the story they are, and the more we know about them. This is usually defined best by action. Don't bore the audience with monologues explaining who they are. Have them demonstrate who they are by what they do, how they act and how people react to them. Sometimes even some of our favourite characters say one thing and do another, which is general human nature and makes that character seem more human.
Once you've created your character, the next step is to put them into conflict. It's what gets in the way of what they want. You must never make it too easy on them. Get them in trouble - conflict is what makes drama and comedy. Conflict also comes from what the characters fear - force them to face what they fear the most.
These rules apply to ALL your characters, not just the main. If you have someone come into a room for one line, they should be a fully developed character. The issue here is you don't have the space to develop them for the audience, but you should know who they are and why they act. There is an inverse ratio that the less time a character has on screen the more broadly that character is sketched. Sometimes all you have is an attitude, but it will be enough to make the scene more interesting.
Another thing to remember is that you need to define "real" every time you start a script. Every film has its own reality. Every film is a world that has been created with its own rules made up by the story teller. They audience doesn't know the rules but they sure can tell when they've been broken. The world is not as complex as real life. It can't be. So that means that the characters can't be as complex as they are in real life and dialogue can't be as mundane as normal conversation. It has to be much more efficient. The character has to be clear with enough complexity to be real and interesting. Somewhere between real life and caricature is where they exist. Not as simple as a cartoon but not so complex that they are confusing. Plus they need to fit within the reality of the world you have created.
Another issue is when a writer violates a character for a line or some plot function. We all have watched something and said "Oh they wouldn't have said that." Never violate a character. If the line doesn't fit the character - delete it. If the line is really good, save it for another character. If the character is uncomfortable in the plot, then you have something wrong in your outline and your concept of the story.
Make your characters active and not reactive. If the characters never actually do anything then your audience will not care.
Basic human motivations:
1. fear
2. love
3. greed
4. power
5. jealously
6. revenge
7. desperation
8. anger
9. hate
10. sorrow
11. joy
12. lust, obsession, infatuation
13. pride
14. curiosity