The ground foundation of any website, understand the HTML5 skills and utilising the best practices can get a great website developed from the start. I speak of this from experience... seriously my tutor at college made me hand write a basic HTML page.
CSS is becoming a very powerful beast over the last few years and in recent additions the ability to add animations just by using CSS3 and have media queries to check the users screen size has opened up many doors to make impressive websites on both desktop and mobile.
Everybody loves data! Who doesn't love data? With the use of PHP and MySQL you can have that great Content Management System, store information from what your users have entered including orders. These two in conjunction make the icing on the web development cake and makes your life and your users just that bit more easier.
WordpressWordpress is a great CMS as it has a great support out there on the internet. Decreasing the time to develop a website and get you web presence. Though without back end knowledge it is not flexible for design.
BootstrapOne of the best mobile responsive HTML frameworks around! Great to start development of a website and a good foundation for any.
Expression EngineExpression is a CMS made for a front end developers. Allowing users the freedom to add their own content and the flexibility for a web designer to build a framework around the CMS.