No, don't start at http://www.w3schools.com/
. w3schools.com is the worst resource for web design and development on the net. Half the information there is either out of date, incomplete, or just plain wrong
If you know nothing about HTML/CSS you have two choices. If you can afford it buy a book or go to a tutorial site like http://teamtreehouse.com/
If you don't have the money just google html tutorials and css tutorials, and you'll get hundreds of results.
Once you learn the basics the only way to become an expert is to BUILD WEBSITES
. The only way you'll learn is by doing, making mistakes, and repetition.
There's no quick way to become a HTML/CSS expert. Be prepared to dedicate years to learning.
On a side note. If you want to make a profession out of web design you'll need to know more than just HTML and CSS.
The "Web Designer" is a dying breed. Just building sites with HTML and CSS just doesn't cut it anymore when it comes to employment. You have three career paths to choose from.
- Frontend Development
- Backend Development
- Two Tier development
Frontend development will involve have knowledge in graphic design, UI design, HTML , CSS, and Javascipt.
Backend development involves knowing server side languages such as PHP, Ruby, MySQL, .NET, etc.
Two Tier knows a bit of both Frontend and Backend.
From there you should pick something as a specialty, as there is just so much out there no one can know it all. Like some people make a great living just off of WordPress development, or node.js development.
So, like I said it'll take you years of learning to become an expert, but don't let me scare you off. If you think it's something you'll enjoy. Go for it. Web development is very rewarding and fulfilling. It just won't happen over night.