So this might be useless to most, but I must be getting denser in my near-middle-agedness because it took a couple minutes to figure out how to leave Buyer/Seller Feedback, even though it was super easy once I figured it out. I am under 40, run a software company, started my career as a software developer, and have been active on various forums for 15+ years, so I'm not a complete idiot on the internet.
In the spirit of giving to a community I'm trying to get more involved with, here's a quick guide for how to leave Buyer/Seller Feedback on Head-Fi, hopefully littered with enough keywords in the title and text to make it bubble up to the top of searches on Head-fi and the Googles for anyone searching how to leave or create buyer or seller feedback on Head-Fi. See what I did there.
Step 1: Buy or Sell Something on the For Sale Forum, then offer to provide feedback (and ask for the same).
This is tongue-in-cheek, but I know I sometimes need an occasional reminder about good communication, fast payment, good packaging, etc. Golden rule and all.
In my case, I bought a Topping D50 from @pataburd. He was great and quickly provided feedback. However, I was a little slow, since it wasn't immediately intuitive
Step 2: Providing Buyer/Seller Feedback on Head-Fi
Turns out it's super simple and similar to other Forums I've been involved with.
First, click on anyone's user name from a post, message, etc.
A popover/modal will display like this. In my case, it also displays a creepy, poorly decorated gingerbread man that my son chose for my profile picture.
Then, click Click Trader History (the fast way) or Profile Page (extra clicks).
Clicking Trader History will take you to the page below. If you click Profile Page above, the link to this page is on the left column of profile pages under profile pictures and is labeled Trader History.
Click Submit Feedback under Selling History if you want to leave feedback for someone you bought something from and vice versa.
From there it's pretty straight forward. Just leave your feedback and submit.
Hopefully this makes it easier for others in the future leave feedback for the first time.
In the spirit of giving to a community I'm trying to get more involved with, here's a quick guide for how to leave Buyer/Seller Feedback on Head-Fi, hopefully littered with enough keywords in the title and text to make it bubble up to the top of searches on Head-fi and the Googles for anyone searching how to leave or create buyer or seller feedback on Head-Fi. See what I did there.

Step 1: Buy or Sell Something on the For Sale Forum, then offer to provide feedback (and ask for the same).
This is tongue-in-cheek, but I know I sometimes need an occasional reminder about good communication, fast payment, good packaging, etc. Golden rule and all.
In my case, I bought a Topping D50 from @pataburd. He was great and quickly provided feedback. However, I was a little slow, since it wasn't immediately intuitive
Step 2: Providing Buyer/Seller Feedback on Head-Fi
Turns out it's super simple and similar to other Forums I've been involved with.
First, click on anyone's user name from a post, message, etc.
A popover/modal will display like this. In my case, it also displays a creepy, poorly decorated gingerbread man that my son chose for my profile picture.

Then, click Click Trader History (the fast way) or Profile Page (extra clicks).
Clicking Trader History will take you to the page below. If you click Profile Page above, the link to this page is on the left column of profile pages under profile pictures and is labeled Trader History.

Click Submit Feedback under Selling History if you want to leave feedback for someone you bought something from and vice versa.
From there it's pretty straight forward. Just leave your feedback and submit.
Hopefully this makes it easier for others in the future leave feedback for the first time.