That really depends on you and your preferences.
I would recommend finding a good book which takes you through a subject - HTML, CSS or whatever - in a logical manner. The problem with online tutorials is that they tend to cover just one aspect or technique, and you can end up with a rather "bitty" understanding of the subject.
Personally, I don't find it easy to learn from video tutorials at all, and they generally suffer from the same problem of covering just a single area.
There are also various online courses - paid or free - you might want to look into.
Have a look around the forums, as you'll find a number of threads offering suggestions for beginners' resources.