How do I evaluate design

Evaluation begins before you open the file. The first question is not 'is this beautiful?' but 'does this serve someone's actual need?' Good design tends to dissolve into use — you stop noticing it because it works.

At senior levels, evaluation shifts further still. You start reading design not just as craft but as argument. Does this decision hold up in a room full of stakeholders with competing priorities? Can the designer explain why, not just what?

The deepest test is durability. Strip away the trends, the palette, the typeface. What remains? If the answer is a clear intention that serves real people, you are looking at something worth keeping.