Do you paint "bad" (whatever that means) because you have shaky hands? If it is because of this, you might consider dipping your miniatures.
While dipping is not really considered "painting" by guys who like to paint, it IS easy to do and yields good results.
A quick google search found me more instructions on how to do this than I can count. One is here: (not mine)
http://gfbrobot.com/2010/12/03/andrews-guide-to-dipping-minis/If it is not because of shaky hands but because of lack of skill, then dont dip, but practice a lot. Some rules
1) Use basecoat! black or white will do, although I prefer black because you have instant shadows on your miniature
2) Thin down paints!!! Most badly painted minis I saw just were raped with thick paint so that any detail was gone. Rather do 2-3 coats of paint than 1 thick one.
3) use a thin brush, keep it in good shape.
4) highlight either by
a) using wash: Paint miniature with base coat, use VERY much thinned down dark paint (black for example) and apply generously onto surface (this works good on hair or chainmail). Let it dry and paint the highlighted areas with base colour
b) using highlighting: take base colour and make it a bit darker with black/brown/dark blue/red (whatever, just make it a bit darker): apply, let it dry, use base colour and only paint the highlighted areas, then use lighter version of base coulour (lighten it with white or yellow or...), apply only to the most highlighted areas.
What you need: patience and some time. A good mini doesnt paint itself in 10 minutes (unless you are a skilled speed painter).
questions? Ask:)