Do you remember our initial workflow chart from Chapter 3?
I was insistent that your workflow pretty much be "edit, check it, then go back and edit some more". The main purpose of visually checking your theme in Firefox, after adding each piece of code, is to ensure it looks fine; if it doesn't, debug that piece of code. Running a validation check as you work doubly ensures you're on the right track.
So, your workflow ends up looking something more like this:
You want to work with nice, small pieces or "chunks" of code. I tend to define a chunk in XHTML markup as no more than one div
section, the internal markup, and any WordPress template tags it contains. When working with CSS, I try to work only with one id or class rule at a time. Sometimes, while working with CSS, I'll break this down even further and test after every property I add to a rule, until the rule looks as I intend and validates.
As soon as you see something that doesn't look right in your browser, you...