Hi
it isn't easy. Yes a wage can be made, but it takes not just hard work, but smart work, built upon skills, musical and non-musical... and it will take a bit of trial and error to gain experience.... but that is to be expected.
what makes a difference? Viewing it as work, not just a hobby helps. A willingness to work on the unfun stuff that is necessary. The exact skills vary depending on your role. A jobbing musician requires similar though different skills to a singer/songwriter who is also an artist. Session musicians need different additional skills to actual band members, or members of an orchestra.
The he ability to learn from others, and not repeat their mistakes or your own is useful. An ability to network and find and develop opportunities. A professional attitude, diligence, and loads of hard work. Find and develop contacts, make friends in the biz... the list goes on.... loads of stuff many musicians neglect.
Most musicians have other jobs, of all kinds... generally day jobs because most gigs are in the evenings. Flexible jobs help, though there is a balance to be had... more money comes in handy, but it usually comes with less flexibility, and more commitment.
Gotta dash, will try and get back and write something more...
cheers
john