I will add my own agreement to this as well Sink. Nothing will ruin a model like paint on the wrong spot and it is something I have to continually check for myself. You don't have to be an -incredible- painter if you are a clean painter. It makes all the different in the world. Keep at it, make sure you get a nice smooth coat on for each layer and touch up the spills and you will suddenly see vast improvement in your minis.
Oh, one other thing: grey makes for a terrible contrast with most things. Try to avoid it as a main colour and you will be much happier.