I read this terrific article "How to Introduce a Character." Although it was written for novelists, the same character development strategies apply to screenplays. Try these tips:

1. Provide the character with a solid background study.

2. Have them carry an obsession or two.

3. Emotional crutches.

4. A chance to be ‘one of the guys’.

5. Be adversarial.

6. Sharp wit. Sharp Tongue. Pretty self-explanatory.

7. Healing relationship.

8. Secrets. Plenty and big.

9. Career.

Check out the entire article on Black Literature Magazine.