Fluency is something which takes time. Expect to always be working on being fluent -- in any language.
Pretty much everybody designs a core HTML file from which they work. You should too as there's no reason to re-do the same thing over and over. Find the flavor of HTML or XHTML you like and create a template with all the tags you want.
Learn XHTML before HTML. You'll be a better person for it.
CSS should be learned with table-less design in mind. See
css Zen Garden: The Beauty in CSS Design for guidance in getting started. CSS will be much more time consuming to learn properly than XHTML.
Unless you're "just" a designer, this knowledge base won't help you do much. Learn a programming language or 2 as well. Javascript will be a necessity (unless you use that Microsoft crap). PHP, Perl, Ruby on Rails, or Python will do you well in terms of actual programming
for the web (and in the order listed).