your best bet is to invest in a regulator (preferably with a moisture trap)
just go to your hobby shop...ask for an airbrush regulator and moisture trap and they should be able to set you up.
The moisture trap is invaluable it stops water from ending up in your paint! The regulator will have a dial where you can set your air pressure (PSI).
Modelers tend to spray between 5-35 PSI depending on preference and what you're doing.....experimentation is key...get an old piece of junk model and have a hay day! Try low...high...thin & heavy paint! Just find out what does the best for YOU!
personally I have had great success with Tamiya paints at around 15-20 PSI at a 1:1 thinning ratio...this gives the flattest and truest paint covering for me! but for others style it may not work!
again...experiment on the junk then turn on the blower and spray on your next museum piece!
good luck
James