First of all I would just be casual. a person is a person no matter what sex they are. You could ask them what they are doing or how's it going. I would say hi or something first to see if they are...
You can ask a question and answer your own question. You can then ask another question. If you ask a question that has already been answered you will see that in the asking process.
It should be "May I ask you a question?" because you are asking permission to do so. will you make a question "how to write a question" cause i dont know how
if you wanna be his girlfriend, ask things you like about a man. for example, i like dogs so i would ask if he has a dog or something. another thing, be yourself