So, the very first thing you need to do is gain a Paralegal or legal qualification or at very least get some paralegal training and then, as much experience as possible. 

This does not have to be with a solicitor or barrister, because nowadays you can gain the relevant legal experience by working in a variety of different employment environments. 

Amanda Hamilton talks through the steps of setting up a Paralegal business in The Barrister. 

Source: www.barristermagazine.com