I think it's important that we are able to follow a recommended way to quote from the Quran so that posts here look and feel coherent together, and hopefully all maintain a high standard.
It also means we can have a place to point people when they are new to the way we do things.
There are also some things that we should consider:
Links Are Good: It's always very good to add a link to the website where you read/copied the Ayat from (in case you were using an online Quran source).
Links Only Are Bad: Leaving the link only is not good becuase 1) websites are not guaranteed to be permanent and might shut down and 2) people don't like clicking links and opening more browser tabs in order to benefit/participate. Please Copy the Ayat to the question/answer you are posting beside linking to the source site you brought them from.
The Arabic Text: English translations are good, in fact they are more important than the original Arabic text of the ayah as most of the users/visitors cannot read Arabic. But the original Arabic text is still important and should be always included, becuase there is only one Arabic text, while there are many translations. This highlights two points:
Include the Arabic text of the ayah as much as possible.
Mention the name of the English translation that you are quoting as much as possible.
Those points are not mandatory, but are recommended for better citation and user experience in our lovely site.