Novice question

[mi_nion]

Can someone point me in the direction of a coding for dummies or beginner coding comm? I have the Tranquility II layout on my LJ, but it's a bit plain. I'd like to organize the sidebar into boxes for a cleaner appearance & maybe add a banner header but I don't know anything about coding. I would however like to learn. I'm at work so I may not be able to respond to everyone's replies, but I'd really appreaciate some help.
ETA: Managed to get the header up.
x-posted