I don't want the paint job to look like total crap,
This is a frequently brought up topic. I rattle can a bike frame every year or so. Mine won't rival a factory paint job but they don't look like total crap either. My paint jobs also don't chip easily and chipping is the frequent "knock" that I hear on rattle can paint jobs.
I think that surface preperation is the #1 key. I use a chemical stripper to remove all of the old paint. Then I prime the frame and start the sanding process. When I get the entire frame as smooth as I want the final paint to look, I reprime the entire frame and let it cure for at least a week.
I recommend practicing with spray painting something that's made of tubeing. Start with a very light spray in the hard-to-reach places like the seat tube and bottom bracket clusters or you'll get runs when you try to fill them in later. I've fallen in love with satin black. It's easy to get even coverage and it doesn't scream "home paint job!". Let the paint cure for at least a week before attempting to assemble the bike.
Doing it my way probably costs about 1/3 to 1/2 the price of having the frame powder coated but I also get the satisfaction of having done it myself.