Theming for a dummy?

I'd really, really recommend that you start theming using the Zen theme (http://drupal.org/project/zen) ; it's the perfect 'Just add CSS' introduction.

I used it for these two wildly different sites; took about a day apiece :-

http://www.electroluxfloorcare-imagebank.co.uk/

http://amplifires.co.uk/

Pete.

Start from scratch can be nasty.
To just modify an existing theme and see what happens, seems to me more pedagogical :)
I like the style of chameleon, without template.php, callbacks and with everything just in one file.
To try that just copy chameleon.theme, chameleon.info and style css into a new folder inside "sites/all/themes/mytheme", and then Replace every "chameleon_" inside .theme file for "mytheme_". Also replace file's name for mytheme.theme, mytheme.info.
.info can be something like:

; $Id $
name = My theme
description = As i said this is my own theme.
regions[left] = Left sidebar
regions[right] = Right sidebar
features[] = logo
features[] = favicon
features[] = name
features[] = slogan
stylesheets[all][] = style.css
version = VERSION
core = 6.x

Just play with that , and you'll learn a lot

good luck!!!

I can give you a great tip, and not wanting to sound obtuse or anything, but "nothing seems to work" is not much to go on when trying to give good advice. Its better to be very specific with the questions, then we can give great answers:)

For example:

Whats not working?
What are you having a problem with - specifically which technology? CSS, HTML, PHP, Drupals theme system?

Start from scratch vs Starter theme? Well, Zen is good start. Framework theme, Blueprint and a few others are also a good start as well.

Frankly, I build from scratch for really custom sites - I usually pinch the preprocess functions from Zen but build the layouts from my own collection of CSS layouts (I have about 40 that are all A grade browser compatible) and use the default tpl files as a source for all the PHP snippets.

I use Eric Meyers reset CSS (modded a bit for Drupal, the Blueprint theme has a good one) and I've built my own base html-elements.css (typography) and forms CSS that I use in every theme.