glock,
I'm certainly no expert on paints, but basically the difference in the types is what is used for a medium or carrier for the paint pigments (the ground up stuff that gives the paint it's color).
Acrylics are water soluable and can be thinned with water, alcohol, or the manufacturer's thinner.
Enamels and oil paints use paint thinner or turpintine. Model paint manufacturers again have their own brands of thinner. Some of the commercial paint thinners can be bought as "oderless", and while not truely oderless, they are certainly better than the regular types.
Lacquers are thinned with lacquer thinner. Which will also clean up (but I wouldn't use it for thinning) just about any other kind of paint. It's about the strongest smelling of all paints. Most lacquers will also eat or at least craze most styrene, so you need to use a primer of some sort.
Lacquers dry very fast. If airbrushing, it's actually possible to have the paint dry before it hits the model giving a kind of grainy surface.
Acrylics dry the next fastest, then enamels, and finally oils the slowest. Note that there are some agents you can add to your paint that will slow down the drying of the paint.
Lacquers should not be used over any other type of paint. Enamels can be used over lacquers but not acrylics, and acrylics can be used over either lacquers or enamels. Oils are usually used in such small amounts and thin layers that they don't have any problems over other paints.
No matter which paint type you use, you should let the paint dry for at least 24 to 48 hours before painting on another coat. Especially if switching to a different kind of paint (i.e. putting enamels over lacquers).
As was mentioned above, you should use a barrier layer between coats if you don't want the paints to interact. Others here can better tell you what to used for those.
Oh, one more thing that is especially true of acrylics, one manufactures thinner may not be compatable with another's paint. I use the manufacture's recommended thinner when thinning paints, and something more generic and cheeper for cleaning brushes, etc.
I hope all of this answers some of your questions. Good luck and welcome to the forum.