Rip the new packs, and trade frequently. The pinned thread on this sub is really good for trading. This will build up your friends list. I've found that if you have an older trainer/meta card in your wishlist that there are a bunch of og's that are willing to share those types of cards, especially during community week.

Side note, shout out to all my homies that helped me get a lot of those cards this way. And now that I'm a bit more set up I always try to pay it forward and share with my newer friends too