I'm not sure if my way is faster or not but here goes...
I have a core stylesheet that I apply to most websites. I'm going to cut and paste those core styles into the new file for the new site. Those are the sitewide styles. I'll modify colors, margins, padding to coincide with the new sites overall look and feel.
Anything after the core styles I'm going to add on an as needed basis. If I find I need to create a style for a page and it is a one time thing, I'll embed that style in the <head></head>. If I feel I'm going to reuse that style, I'll place it in the external CSS file. I'll keep that file open and minimized for quick reference and editing.
EWD's method of naming styles would not be satisfactory for me. .style1, .style2, etc. is not an intuitive naming convention.
You could also do this the reverse way. Build the page, style away, and then save those styles to an external file. But, with the default naming conventions, it is going to create a maintenance nightmare. You'll have to look at a page and verify what the heck .style45 was. ;)
Or, you'll need to rename them appropriately before tucking them away externally. They will now appear in your style menu when working in WYSIWYG mode (the style sheet must be reference in the <head></head> of the document). You select the element or text, go to your style menu and select the appropriately named style you want to apply. You have both block and inline styling available to you.
Then, to take this one step further, you may develop additional style sheets. These may be specific to a certain section of the website where you are sharing those styles across a group of pages. So now you end up with two external CSS file references in the <head></head> of your document.