‘It has to be good’ is probably the most accurate guideline you’re going to get. Sounds ridiculous, but if you think it through… what would an official document on quality standards contain? It’s impossible to specify what makes a design ‘good’ in any kind of quantifiable measures.
Yes, you could have some kind of list that says something like ‘fonts must be current and in-keeping with the design’… but what does that mean? What is in-keeping with the design and what isn’t? Or it could say, ‘colors must complement each other’ etc etc. It’s impossible to have a document that specifies what you can include and what you can’t… what looks good and what doesn’t, which fonts are ok and which aren’t.
Why? Because any such stipulations would limit creativity and would be based on existing items… they couldn’t take into account items which haven’t been submitted yet. The ‘rules’ of today can rarely predict or plan for the designs of tomorrow.
Yes, it’s a bit of a wishy-washy explanation, but you’ve got to think to yourself… if you were the head of the review team for GraphicRiver, and you had to write a document on quality standards, what would it contain, what would it look like? Is it possible to objectively define exactly what is in and what is out based on specific yes/no answers?
Of course it’s subjective… what else could it be? Training could be provided using existing items or items that had been sent for review… what we like, what we don’t like, why something was accepted, why it was rejected… but a subjective decision is going to have to come into play every time a new item is submitted. An item which wasn’t used as an example during training.
While you’re imagining being part of the review team… imagine the hypothetical situation of somebody in the forums insinuating you and your team might be incompetent. Imagine how that inspires you, and makes you really root for that person to get their items accepted.