How to know if a website is good?
Please help me to know
what you really like on websites?
What you really feel in 10 first seconds?
What make you happy when browsing?
What make you come back?
What do you define as a good website?
Why don't you ask your customers directly. Get a feedback form, make it easy and quick. There is no harm in interviewing your customers. They would feel good that you care enough to change your site according to what they prefer. Yes, there will be some customers who would not have the time. If 90% of your customers seem not to bother to fill the feedback form, just go to plan B and A/B test your site. A/B test each element one at a time, like contact forms for instance.
What I would define as a good website is, not the one that is pre-built based on stereotypical usability standards but one that is constantly changed according to real time users of the site. Mistakes maketh a website perfect so don't be afraid to experiment. (If you really want to play safe, take a look at your competitors that have many site visitors + high conversion rates, do some research of your own in your niche.)