As one who has many stars, I'll add to this thread:
I've spent a decent amount on the site, and I can honestly say that it is absolutely the least efficient way of making FG (Forum Gold).
As Randz66 said, many go by the 2/3 rule, but many also don't, for a few reasons.
# of Posts can be heavily exaggerated by spamming GC (General Chat) threads where there's almost no moderation. On a day where I was very active on GC, I've managed over 100 posts in a day. Many of our resident GC members have over 50,000 posts. This is why some members think it's a bad metric for trading.
Join Date, in my opinion, is the best, but nothing is 100% safe. There are too many bad eggs who go for years without ever scamming, and then when they decide they're done with JSP, use all of that trust and a good join date to scam a bunch of people before getting locked
Total Gold is a terrible metric, because you can literally have as much as you want, depending on how much $$$ you're willing to spend, or if you spend lots of time in BnP (Bar and Pub Games. You can gamble there)
The best thing to use is common sense. If something sounds too good to be true, it probably is. If someone is in a big, big hurry to make a sale, be cautious. Never be afraid to back out of a sale if it seems shady
Until the item is given or FG is sent, the sale is NOT final.
You will get some flame for being such a new member, but don't listen to the haters, some of the people I trust most on this site are newer members
Welcome to D2JSP!