A Wider Audience

Unfortunately all surfers and the equipment they use are not equal. Variations in both computers and browsers need to be allowed for when composing pages. The two main problems being - variation in screen size and visibility - and browser compatibility.
However the situation isn't anywhere as bad as it first appears - and quite simple techniques will allow most surfers to view your pages.

Variations in visabily can be overcome by using relative font sizes. Changes in character size can be specified by - actual size - or a change in size. Relative font size is defined by font="+2" or font="-2" or whatever. This causes a change in size over the default setting for the machine used for viewing rather than forcing a size that may be too small. The viewer will still see headings larger that other text - so that the overall look of a page will be similar to that intended. Absolute sizes do not have a sign before the number.
Other font definitions are:

SMALL - Smaller text

STRIKE - Strikeout

STRONG - Strongly emphasized

SUB - Subscript

SUP - Superscript

Browser compatability problems can be avoided by only using the more common and well established tags. i.e. lists - tables - etc.
My own Web Site sticks to these - so feel free to save some of the pages and examine them in a text editor.

There are a lot of fancy bells and whistles usable in some browsers - but you can produce a good site without them. Don't get side tracked from the main function - which is to clearly present information - unless of course you are building of an entertainment site.
Unlike paper - blank lines have a very small impact on the size of files - and can greatly improve readability - so use them libraly.