I've been a brush painter since the '50s. What paints you could get then were mostly gloss and no fancy colors like olive drab. (I used equal parts red, yellow and green). I have done some air brush work, but my wife has asthma, so that means brushes on the patio.
Over the years, I have adapted my skills to work with aircraft and armor schemes that could be brushed. I have done a lot of RAF aircraft, since their camo patterns were hard-edged, something a lot of air brushers forget. I still haven't managed a natural metal finish to match airbrushing, but I keep trying.
I use Humbrol and MM, mostly. Always thin a new container when I open it up and also drop in four or five BBs as pigment agitators. Almost never go for gloss colors, since flat colors dry more evenly. You can always overcoat with Future.
Sometimes when I'm feeling ambitious, I'll use dry-brushing to get a soft edge on colors, like the tri-color USN scheme in WWII.
Good luck. You don't have to have an airbrush rig to turn out quality models.