Following these steps, you can sell your items or currency for other currency items easy and fast.
There are two official types of player shops:
Most players are using the first method, utilizing their Premium Stash Tabs.
Both Methods are read by shop indexers like the official trading website.
Most players will have bought at least one premium stash tap. For players that are still missing this huge utility feature and are willing to wait sometime to save a little bit, there are Stash Tab Sales every few weeks, with one almost every time on the second weekend of a league start. Check the official website or the wiki front page for the current news.
If possible, you will want to use an empty stash tab for your shop, this will allow you to only put items in there that you actually want to sell. You might want to give the tab a unique name, you find it quickly if you get a trade.
Set the tab to public (and possibly renaming it).
Select how you want items to be priced.
If you have an item and you know what you want other people to pay for it, you put the item in the shop tab and press right-click.
The field on the right is used to set the requested currency. The most common trading currencies are the Chaos Orb and Exalted Orb. Once you set the price with the small checkmark, the note field will be filled with the information you put in and it will be shown below the item.
When trading for currency, you can use tricks to get the desired price on the bulk item exchange or in simple words "currency and consumable market".
Let's say I wanted to sell my 20 Harbinger's Orb for 120 Chaos Orbs.
The way you do this is by using a fraction expression, don't worry this is simple to understand.
You use I want / I give and put the currency you want in the box.
For this case, it would be 120/20 Chaos Orb on my Harbinger Orb.
And what if I want to sell more than one full stack, you might ask. Then you put your desired trade on one item stack and put the rest of the item in the same tab, or another public tab. The trade indexer will find all your public items and add a "stock" number so other players might request more items, but at the exact same ratio you set.
In this case, let's say I wanted to only trade stacks of 20 Harbinger's Orb, but I had 140 in my tab. A player on the trade Website might ask me to sell him 100 for 600 chaos orbs. It's the exact same rate, but a higher number.
Side note: Remember the maximum stack sizes of currencies and your limit of 60 slots. This means you can only fit 600 chaos orbs in one trade window. Trades above this volume should be split up into several trades or use higher valued currencies like the exalted orb to avoid scams and miscalculations.
On the official forum, you can find the trade section. In there, some players create posts with the items they want to sell. This way of indexing your items is completely free but is connected with a lot more manual work. Once you created your post in the appropriate category, you open your profile in the top left, go to your stash and left-click the item you want to sell, and warp it in a spoiler name with the price you want to sell it for. Be warned that this method is very outdated and not all indexers will find your items this way.
PoE Overlay allows you to search and buy bulk items. Then, you can send requests one following one fast.