I see the "trust" function (i.e., +1, -1, etc.) on the forums. How do you gain trust?
Do you really need to care about "How do you gain trust?" Gaining trust score is a natural process; You gain it
+ve,
neutral or
-ve just doing trades or providing services or put more simply by being a valuable and helpful community member. Doing 1 or more of the aforesaid things make other community members here leaving a trust feedback to your profile (if they wish to do so) and your trust score will reflect those feedbacks.
By the while, why asking such a question like a wannabe scammer while using the search form here on bitcointalk can find you all the guides & help on the topic?
There's a field for the "Reference Link" in trust. I assume this requires some sort of post for validation. Perhaps a link to accounts on other sites would serve as a good source?
Unreferenced trust feedback bear low to no credibility. Trust from outside sites bring no value at all since it was rigged by sockpuppets & other abusers. You should do real trades and other members here will give you feedback based on them, putting the references in the Reference Link field.