Hi, welcome to DPF! 🙂
I've only been collecting and trading for about 8-9 months, but the best thing I've learned so far is building up traders is super important. For one, you never know what someone else might have (a character they're not too interested in, but you are!) and if you start wanting harder to find pins, even if the traders you have aren't equal in value 1:1, you will sometimes have an opportunity to trade multiple pins for a harder to find pin you really want. 🙂
Also, if you don't know about counterfeit or scrapper pins yet, keep a close eye on the pins you may want to trade with Cast Members at the park. There are several posts on this forum you can read up on about this.
HAVE FUN!
--Melanie