1.) Make sure your Steam account is READY TO TRADE or does not have a trade hold (to check, try sending a random trade offer to someone and see if there's a warning at the top). 2.) Set your Steam Inventory to public to enable trading. (To check: steamcommunity.com/id/me/edit/settings) 3.) Include the trade offer link in the comment section (you can find it here: steamcommunity.com/id/me/tradeoffers/privacy). 4.) (Optional) Include your Steam profile link in the seller's note.