Step 1: Check their engagement on the forum.
Click on messages. See the engagement, and you should be able to gauge to an extent.
Step 2: Check their Messages to reaction ratio. There is no hard and fast rule. However if someone has 1500 messages and just 100 reactions it means they have not engaged outside of the WTB, HAF or their own thread. This is not necessarily bad, but sometimes it's a tell.
Step 3: Unrealistic promises before purchases is a huge red flag. Any good legit seller would under promise and over deliver.
Step 4: This opinion of mine can be controversial. But extensive use of the words "bro", "dear", "mate", "sir". I mean extensive. Example every line they send will have this word, before and after the sentance.
Step 5: If they are too pushy and offer Unrealistic promises like lifetime warranty or say 50% off if you order within 1 hour.
Step 6: Use your instincts.
Finally "Never spend more than you can afford to loose" when you do the first transaction, slowly scale with a given seller after you have done business with them for a while.
But however irrespective of how many checks and balances you have in place, there will be times when things are unavoidable. I get scammed from time to time. Take the experience as a learning and avoid in the future. Nothing is fool proof.
On a positive note, not everyone you meet is a scammer. There are a lot of sweet and genuine guys.
Good luck
