Hello #Suraif ,
The first thing you should consider is that you are going to work on any kind of web site. Example entertainment, News, Business, education, etc.
After that you have to make your website . If you want to have a website design based on SEO, you should pay more attention to your Website’s Responsive Design.Responsive design is important for phones. The coding should be written in all sorts of roles. This is a very important issue.
The developer should design a suitable designer to suite.Not only that, the meta tag, the meta description , URL structure These three should be very careful.maximum of Meta description should have 160 characters. The meta tag should not be over 60 characters.
And the things you need to keep in mind:-
1. Don’t overload page with visual , graphic, animations .
2. consider heading tags .
3. mobile friendly [its like seo friendly]
4. HTML 5 is full help for SEO
5. Great UX.
Apart from that, the customer’s dependency on the design is in your hands.