Part of being a good UX designer isn't having the right answers, its about asking the right questions. Knowing what the questions are will lead to moulding the design from a ill defined shape, to a considered and appropriate product.
A designers and developers job is to decide and execute a response to a brief. To, working with the client, weigh up all the information in front of them, and craft the right(est) answer. Thing is, with design, while we can have measures of success and use analytics, there is always the subjective element to it, and never one clear right answer.
I sometimes get worried I'm playing devil's advocate too much and my questioning and prodding of a design is interpreted as slight on someones work. Its not. Far from it, if I'm questioning it, I think its good, and want to input by posing questions, to ensure that the UX is a as good as the visual.
With that in mind, I thought I'd jot down some of the questions I find myself asking again and again, which might be read as condescending deadline shifters to some, or a good checklist to others, but regardless, these are important questions that all designs need to go through.
Are the colour contrasts meeting AA standards?
Does all messaging work without colour? Will someone with all types of colour blindness be able to understand?
Can I tab through using a keyboard? Is it clear what element I'm on?
What does that sound like from a screen reader?
Whats the browser and device support? Do the fall back to a workable state?
Is the browser filtering only the CSS it needs? Modernizr being fully utilised?
How does that work on touch?
Is the markup semantic?
Users and goals
What demographic is this aimed at? Is the copy and interaction appropriate?
What does the user need to feel fulfilled at the end of the journey? Do they need positive feedback or additional signposts?
What happens if I leave halfway through the journey? Can I pick this back up? How do I do that?
Are there project goals? Does this align with those?
What is the hierarchy of buttons? Primary, secondary and tertiary?
What are form validation messages? Do they stand out enough?
Whats the most important thing on there? Is their a hierarchy from most to least important?
Is there a style guide?
What's the naming convention for classes? BEM?
Is everything commented so another designer can pick up the code base and run with it?
Note: This isn't a definitive list, and I'll probably add to it as more pop to mind, but it does serve to show the mindset of good UX.