Hey Mike,
Here's my experiences with making my decals. First I tried following the instructions with some decal papers for use with ink jet printers. Not worth the time or the effort. The product just didn't work very well for me. The colours ran into each other and the definition just wasn't there. If you have a colour lazer printer on the other hand, you're off and running. I don't so I went the to next best solution.
I do all the art work on my home PC, do a couple of test prints on regualr paper to ensure the size and definition is there. Then I save the art work to disk and take it to my local printers with a sheet of decal paper in hand and have them do the print for me. Costs me a buck, but it's a lot cheaper than buying a lazer printer. After I get the decal sheet home I coat it with liquid decal film to protect the colours and then apply like a normal decal.
One of other the things I've learned is always use the white backed decal paper. Number one there are very few printers on the market that can print the colour white so you need to plan for this, number two is that the colours definition is much better on a white sheet instead of the clear one.
Hope this helps a bit.
Happy Modelling and God Bless
Robert