just do it through chat. press enter to bring up the chat window. press $ then enter to bring up trade chat. all the trade chat is in orange text. start off by asking what is a fair price for the spell totem gem. people will tell you what the gem is worth in orbs. Then you should announce in trade chat that you wtb spell totem. if you need a certain orb, you can trade lesser orbs for the orb you need at the merchants in town. you can negotiate a trade; rare items(s) for gem, orbs for gem, or gem(s) for gem. most trades are paid for in orbs btw. just make sure you do all your announcing with the dollar sign ($). then make sure you do all your negotiating in whispers. type @charactername to send a whisper to that player. once you work out a trade, invite the player to your party or tell them to invite you to their party. make arrangements to meet in a town. if they open a town portal, wait for them to come to town. do not jump the gun and take the portal to their location. don't take the portal even if they tell you to. just insist that they come to you. once you meet up you just drag and drop what you are trading into the trade window. before the trade can be approved you must scroll your mouse cursor over the item they are trading to you. once you do that, you click the approve trade button and wait for them to approve. once approved by both players, you're all done, leave the party before you run off.
here's something else that will come in handy. you can show items in the chat box. this is the proper way to offer items, gems, and orbs for trade. first open your inventory screen. then open the chat box. press $ before you enter in any text so that it shows up in trade chat. ctrl + alt + left click the item you want to show in chat. type whatever text you want then press enter. when you do that, it will show the items to other players. if you want to look at items that are being offered, open your chat window, then scroll over the items. it will show you a picture of the item and a list of all the stats. make sure you show the items that you want to trade away. And make sure that you are using the trade chat when you announce that you are buying and selling. if you dont, the mods will give you a warning. chat spammers get suspended sometimes.