How I sympathize with you! Although I am no expert, so I won't be much help. For the site I am currently doing, I tried to (for the first time) axe tables and completely separate my formatting from structure. I'd say I spent a good few days doing this, and I didn't even touch one section.
I think it's something that doesn't go fast right when you begin. But with more experience, it'll get faster. My best resource was right here at SP, where when I hit a wall SPers, esp Paul O'B or DougBTX, knocked it down for me. Keep practicing is my advice!
I've spent a good portion of the last two days on this and I'm ready to go back to tables (gasp, yes, me, for this one layout!).
Two days... If you're sitting with someone who is an expert, then I'm sure you could learn most of what you would need to know in that time. Reading on the net, it would take longer. Experience is important too. I made two full sites in CSS+tables (mainly using table for chuncks of the page, and then using absolute positining to get them where I wanted them) before I made my first tableless site for a client.
I think that getting into CSS layouts is harder than getting into a Table based layout, but once you understand the main ideas behind CSS (Cascading is the most important part) then you should be fine. The main difference between tables and CSS is that with tables, that is all you have: tables. With CSS, there are more tools to learn, and different ones are more sutable to different situations than others.
Okay, just to clarify, I have been using CSS for some relatively simple layouts. This time I'm trying to stack some layers/divs to achieve a particular effect and keep coming up with the wackiest layout ever.
I'm not a total noobie, I guess that's why I'm so frustrated. I can do this, really I can, just not THIS layout. aaaaaaaaaargh!