When you google "Great Character Intros" this site comes up as the first choice. Second is John August's blog.
In fairness I did write mine first. But, really, who wants to hear me over a professional right? John has two or three seperate posts on creating great character intros. When I read them I was like, "Damn straight, I hit the nail on the head. Even the pros agree with my little discovery." It was a nice ego boost.
So, here's a link to John August's articles. Read the man's thoughts. They are $$$. Especially since he does get paid $$$ to write screenplays.
The one thing that I think he hasn't gone into much depth about is that the SCENE in which the (main) characters are introduced should reflect every aspect of that character.
In LETHAL WEAPON, Riggs is introduced at the beach, as a drunk, who protects a dog that bums are picking on. We also find out he is a cop in this scene. The scene nails tone of the entire movie, Riggs "crazy" character, his job, his kind hearted/protective nature, and his fighting skill. Not to mention the scene itself is a great hook.
That is some heavy lifting for an intro scene. And you should expect no less from your own.
Sometime in the future, I will be posting more great character intro scenes, making a series out of it. That is, if I can find the free time.