There are some points which you can follow to ask for a reference:
- First of all, make a good resume so that anytime you get a chance to talk to someone regarding referral you can straight away present your resume.
- Keep your profile updated on social media and start making a connection with people over there.
- Talk to your friends outside if they have any vacancy in their firm ask them for the referral.
- Carry a good command on whatever knowledge you have so that once you get an interview it should not take much time for you prepare for that.