I really gotta stand out against W3Schools.
Its true that some of their stuff is minor, but other times, its a big mistake that teaches flat out wrong, and will make your head hurt when you try to fix it. And even though plenty of people point out their mistakes, they are adamant on not fixing it, which shows their attitude to teaching: if they don't say it, it can't be true. they're not associated with W3C, and their retained popularity is mostly due to the fact that they rank high on search engines (thankfully, others are overtaking). (http://w3fools.com/
Not to mention, their site is far from attractive IMO...
I'm a fan http://www.html.net/tutorials/html/
but I do think the best guides/tutorials are a mixture of simple books and just doing it. Sites like net.tutsplus.com offer resources once you get the basics, and the basics can be learned by googling your question (if you google "html tutorial" or "css tutorial", you'll find plenty! There are also a number of good books and videos out there (I do like Lynda's HTML tutorial, its not that expensive either) that you may want to consider.
However, the best, as I said, is just doing it. Find a site you like, right click and hit view source and see if you can understand it. If not, find a simpler one and try again. I'd avoid trying to analyze forums or blogs initially, as they're more involved/complicated, but you might wanna see what you can do with it.
Fortunately, HTML and CSS are very readable... the CSS property of 'background-color' sets... the background color!