The secret is how you mix your paints. That applies to any paint. I haven't used acrylics much, mostly lacquers and some enamels but the Tamiya acrlyics I have used sprayed very well.
I pretty much stick with 20-25psi and adjust my paints but that's what I'm used to with my brush and compressor/regulator. If it wants to run it's too thin, if it's rough it's too thick. I'll mix the paint and spray a bit to see how it looks and adjust if needed. With the small amounts of paint we're using it's something you just have to get a feel for, there aren't any set ratios. I mix paint in a bottle and drag a little up the side as I'm mixing it. If it's runs back easily and leaves little color behind I know I'm close.
Start out with some light coats just to get color on the model and then go back with heavier medium coats for coverage. I over reduce final coats right up to the point that it runs so it will level as much as possible. Any time you notice dust or dirt in the paint stop right then. Wait until it's sandable, clean it up and recoat. If you've sprayed your first light coats and shoot a heavier coat and discover it's too dry/rough then sometimes you can go right back over that area with a heavier spray and smooth it out. I always try that. Then go add some thinner. I don't have enough experience with acrylics to say what kind of dry/cure times you need between coats.
The smoother you get your color coats the better the model will look overall. Solids are easy, just sand/polish them smooth and then clear. If it's a metallic or pearl and you think you can lay down a smoother coat then sand/polish and recoat. With just reshooting a coat or two you stand a pretty good chance of ending up with a smoother finish. You have to decide.
For clear, I guess Future's ok but it's pretty thin. If I were going to have to do much polishing I'd use Tamiya clear but that's just me. If you use Future and are going to polish then take the time to build up some extra coats. If you do polish then go lightly on edges and peaks. You may even want to protect them (edges/peaks) with tape. If you're familiar with Swanny's website, he says that you can add Simple Green to Future for a higher gloss but I haven't tried it. I'm not certain about the ratio but am thinking it one 1/4th Simple Green. I would think that would give too much of a tint to the Future.
With that said, I hate to polish. I do everything I can to get the finish smooth by thinning. It takes practice and familiarity with the paints you're using. You might want to experiment on another body first.
Tony