I paint in my garage, which still has a dirt floor and many, many gaps for wind to blow through. It's an old, dusty place, with lots of dust and cobwebs in the rafters. Not exactly a proper spray booth...
Here's what works for me:
I keep the big door closed. Always. The man door is kept open, as that is my exhaust area. I don't use an exhaust fan - moving air out means it has to come in from somewhere. Air movement means dust movement...
My compressor has a 20 gallon tank, so I fill the tank and then shut the compressor down so it doesn't blow air out the exhaust.
I wet the floor in the area where I'm standing/sitting. Sometimes I'll water outside the door if it's breezy out.
I lightly blow the dust off of everything ( table, parts, body, etc.) at least 20 minutes before I'm ready to spray. That gives lots of time for any dust to settle. No more than 20 psi.
From that point on, I wear nitrile gloves. No loose clothing, no shirt sleeves.
No paint gets into the paint gun unless it goes through a proper paint strainer. I use a new strainer every time I have to add paint. I use a HVLP mini spray gun for almost all my spray jobs. I find it much faster, easier to control, and easier to hold than a n air brush. That\s just my preference.
I wipe everything down lightly with an alcohol swab immediately before I'm ready to spray.
Then, I use a tack cloth over everything to be painted. Just a light pass. I keep the cloth in a zip-lock bag when not in use. I can easily get a summer of paint work out of a single tack cloth.
Here's the most important part: I don't roam all over the place when the paint is wet. In fact, I arrange it all so I can stand still and spray. Movement creates air movement... and most of the dust in any paint job comes from the painter. Dust in inevitable, in some form or another, so anything that can be done to minimize it shows in the final product.
Hope this helps...