Re: Creating web templates
Back in the day I learnt most of the structure of css etc from W 3 schools stuff. It'll get you enough of a grounding to know what to Google to do what you want if that makes sense.
Re: Creating web templates
If you are coming from an absolute basic knowledge of html/css then I'd agree getting the basics down on w3schools or similar would be helpful.
If you've got a bit more experience then it'd probably be worth learning a CSS framework such as Bootstrap or Foundation. They have their learning curves but will give you tried and tested layout tools that'll get you building responsive and decent looking pages fairly quickly. They'll save your hairline not having to work out why something isn't rendering properly on [x] browser.
I find it's always good to keep up to date with the latest developments - follow CSS tricks or Codrops for some good inspiration.
And above all, keep practising and trying new techniques.
Re: Creating web templates
How handy are you with developer tools in browsers?
Bootstrap is always popular, I found this useful too https://html5boilerplate.com/.
Once you are a bit more familiar with css then this is worth a look aswell http://unsemantic.com/