How to approach networking for 3L recruiting?

Current 2L at a T14. Super grateful to have secured a SA position for next summer, but it’s in a practice group I’ve discovered I’m not really interested in, and I’ve heard my firm isn’t too fond of big changes in practice groups (e.g., going from corporate to litigation).

Since I’ve heard that referrals are important for 3L recruiting, when should I start networking and how should I go about networking while already having a 2L position? Thanks!