What should I look for when critiquing a design, specifically the design of a website?

I'm aspiring to be a front end developer and as far as that goes I am pretty comfortable coding for the frontend. I would like to improve my design skills.

I would like to know what to look for when critiquing a website, what aspects of the website I should look at and what questions to answer.

Any information regarding the way you go about critiquing a design or a website, and any checklists or documents you follow would be greatly appreciated

Cheers.