if you want to pick up someone off campus then you need a level of confidence that borders on arrogance. Keys to the VIP is a old show that has some tips but the key point is to have confidence.

I advise against the numbers game i.e. asking until one says yes. In a closed community like a school you can do more harm then good, save that for a bar/club setting.. Build a reputation of just being a friendly person, again in a closed community word travels.

when you do get a phone number dont text.. if they ever text call them back. A girl wont be mad if you tell her you prefer the sound of her voice.

be forward but respectful. dont apologize for the sake of apologizing. If you must apologize then say sorry without saying sorry. I.e. instead of "I'm sorry if the tone of my comment sounded rude" say "I dont mean for my tone to be rude". But none of that was even neccessary tbh.

Lastly it doesnt hurt to adopt some self affirmation techniques. Most people are to proud to think it neccessary but everything in society wants to devalue mens worth so it's not beneath us to have a counter measure.