"Web design" is a very generic description that spans a wide range of skills and technologies. It's like saying you want to become a programmer. These are just too high level to be of any use when discussing details.
When it comes to creating websites, the type of the website will dictate the technology that you'd want to use and get comfortable with. If you are looking to setup a blog, you can start with existing CMS (Content Management Systems) packages out there and then spend your time either writing the content or customizing the looking and feel with CSS.
If you want an e-commerce site, you can modify the CMS packages to add that functionality or if you have the programming chops, write the back-end (server and database) with frameworks like Rails, .NET, Grails, etc. talking to a database like PostgreSQL, Mongo, CouchDB and so on. You can then design the front-end using technologies like Angular, React, and so on..
So tell us WHAT you want to create and what your level of expertise is and we can put you on a path that makes the most sense..