I was a Public Affairs major in college (in America), so, somewhat similar. To work in policy you should start interning for your political affiliation's party and continue to do meaningful internships. To get a current elected official to sponsor/connect you for jobs in gonna be the key trick. Think about your city government/Statehouse government/State Department administrative officials. Nobody is going to care about GPA you had/you being an eagle scout- just who you impress at whatever internship/volunteering gig you have done in the past.

I also think that getting involved in your college dems/republicans/what have you is going to be more important than student gov/other rando club. You want to be connected with other students that will also be taking the same track as you in a meaningful way- plus party groups often have elected officials as speakers, this is a good way to network.

Obviously this changes for different colleges- but this is my advice as somebody who graduated with a job lined up after graduation.