Tania -
If you need to go beyond the capabilities of an authoring program - and to build a really
good site you have to do some hand-adjusting of things - it's best to learn HOW to build
pages in a plain text editor, inserting tags by hand, because that forces you to focus on
the FUNCTION of the tags, how you are using them, and why you are using them. It's similar
to learning to program in bare "machine language" - you may never have to do it much after
you learn it, but afterwards the rest of the programming languages make a lot more sense.
After you can do that, you'll be in a better position to evaluate authoring programs,
to fix page errors, and to know what parts of authoring programs are useful. As much as I
sneer at MicroSoft's FrontPage, it makes forms faster than I can (by hand), so I create forms
in it and then cut the form out and paste it into the final page.
Until the creators of authoring programs put as much effort into helping you build a
well-structured page and site as they do in making it pretty, you'll have to learn the anatomy
of HTML to make up for it. (structural authoring programs are being discussed, but the
commettees are just now finalizing the standards so it will be a couple of years before the
program that produces a classy page with flawless HTML structure is here)