Ahh, this is really good. ;o; <3
As for tips, the layers and smoothing are your greatest friends.
This guide goes over both (
specifically right here). If you are using a mouse or track pad I'd recommend you use a higher smoothing setting. If you're using a tablet (Wacom Bamboo or other) you might not have to use as much smoothing, depending on how steady of a hand you have (I normally use about 60-70% smoothing with my tablet, and 80-90% without it). I also wouldn't recommend using the paint bucket tool to fill in the lines on the same layer (it gives a white ring around the color). Instead, make a layer below the lines and put your color there. That way the coloring doesn't interfere with the lines. ( don't know how much of this you know, just wanted to go over some of the basic Chibipaint things just incase) qoq
If you need a live example, I'm always willing to do a JoinMe and show you more in depth. (as useful as the guide I showed you is, some people just need hands-on learning, kind of like I did I"D) <3