fine lines with my air brush

Practice, thinning, practice, some more thinning, some cussing, and more practice! 

Andy 

For fine lines, I thin the paint more than normal & turn the compressor psi down.  Hold the AB very close to the surface being painted & move the AB fairly quickly on your pre-determined path..  Takes a lot of practice to find the right combo of thinning/pressure/trigger release for your set up, but eventually you'll find the magic combination that works for you .

Regards,  Rick