Web design encompasses many different skills and disciplines in the production and maintenance of websites. The different areas of web design include web graphic design; user experience design; search engine optimization etc.
User interface design is the design of user interfaces for machines and software, such as computers, home appliances, mobile devices, and other electronic devices, with the focus on maximizing the user experience.
Email marketing is good for your business. Email marketing is directly marketing a commercial message to a group of people using email. Email marketing can be done to customer database.
SEO is a technique which helps search engines find and rank your site higher than the millions of other sites in response to a search query. SEO thus helps you get traffic from search engines.