I am not able to form a gang, I have followed all the instructions but nothing works!! My controller is ok, any ideas?

What instructions have you been following?
It is always easier to point out a mistake if you provide a description of what you are doing.

I remember collecting a crew outside Carl's house and jumping into a car with 3 other persons as being the first time I used the feature.

Your problem may be lack of respect. I don't know how far along the game you are but (if I'm remembering this right) the number of gang-members you can rally is dependent on your street-cred, or something like that.