While you may type your page in a certain font, the person seeing your page may not have their browser configured for the same. So do your typing in a common font such as geneva or courier.
Browsers
Some browsers will support some features of HTML while others won't. What you have learned here is very basic and should be supported by all browsers.
Testing
You should try and test your page on a few browsers to see how it will look.
Other pages
When you come across a page you think is done very well, you can save it as source which means you will save it as an HTML document that you can view later. You can pick up some pointers from looking at the underlying HTML.
Common mistakes
They are:
1. typing in the HTML code incorrectly
2. not saving your changes
3. not reloading after you have made changes (your browser will show the document as it was before you made the changes)
Layout of the HTML document
Try and keep it orderly and structured. When you go back to make changes it will be much easier.
Layout of the page
Look at the HTML of a page that you like. Getting your page to look asthetic and be usable is a challenge. This will involve some trial and error. Before you post the page, have someone go through and test it for you.
HTML 201
This next installment will cover graphics, links, email and backgrounds.