Playing with LJ

Okey-dokey, I am playing in being an advanced LJ user. It doesn't work as well as it could. I changed the style to S2 Component, I filled my limit of userpics, I changed my mood themes, and I am not entirely satisfied.
Actually, I am entirely satisfied with my Kill Bill mood theme – made by be_found, and I am very tempted to put my moods arbitrarily, just to show it off.
But there are other things (I don't have to waste all this time on them, but i do) that I'd like to ask those who already did it.
1) How to make an icon for every entry appear on my page – not only the default one in the corner?
2) How to change colours of the font, other parts of layout?
3) How to put a picture on the background?
4) Where can I find answers on all these questions?