Leaking at the threads, or at the internal connection point?
I've had decent luck with HF's oversize, 3/8", coupler sets. Only rarely do I need to rotate a connection to quiet it.
For Teflon tape at the threads after going around the threads a couple of times, I twist the tape so it makes a high ridge as I go around again, then a final flat wrap.
On my most used compressed air hose, I find that I need to replace the female coupler every few years as the o-ring distorts and doesn't seal when uncoupled, nor when coupled.
And watch out for having some incompatible fittings like industrial vs automotive. Some combinations connect, but leak like mad.
I have used Milton M-style since the early 70's.
I do 3 wraps of Teflon tape on the male end and if it leaks, I put a small dab of pipe dope on the first two threads of the female end.
Just home owner use but still, no audible problems.