Honesty, integrity, communication.
Participation in threads outside the exchange is helpful too. Get to know some of the members. This is definitely a community of people whom try to look out for one another (most members anyway). If someone is too pushy, move on. If someone is apprehensive, don’t take it personally. You’ll establish feedback as you buy / sell.
Seeing as you’ve not sold before, PayPal goods and services is probably the best payment option. Factor in taxes if you plan to exceed $600 dollars in cumulative sales. Goods / services offers a decent amount of security for the buyer and seller.
I try to treat people like I would appreciate being treated. Provide tracking information asap.
Welcome to Blade forums by the way. We talk about knives. I love this place.