not complicated really, maybe knowing a bunch a people that can/will vouch for you can grease the proverbial wheel(s)…you still have to put the work in & have the skills, of course…but it’s basically as follows:
work on portfolio, get feedback, use feedback to improve portfolio, get more feedback.
repeat that process.
if at any point in that process you are confident about the work you have (and really even if you aren’t, you never know what people are looking for) be on the lookout for positions at the spots you’d like to work at and try to establish (or use contacts that you may have) connections at/with those companies and apply for those positions…
good luck with the job search!