Maybe visit Jason Edwards website - very successful NG Nature photographer.
This is his FAQ page:
FAQ
... or maybe Joel Satore
Look up the journey they have travelled to become great natural history photographers.
Many great nature photographers have formal qualifications in the Biological sciences or have (through shear weight of experience and personal research) an extensive/detailed knowledge of nature.
So, along with developing the photography skills, you could also focus on developing your natural history knowledge and bush skills.
All the very best.
Now pick any number between 1 and 200,000 .... (seriously ... pick a number)
... if you picked 143, 225 you are a winner and will be a successful professionally employed nature photographer!!!!!!!!!! (and I'd say odds of 1 in 200,000 ti become a working nature photographer is generous. But some-one has to be that "1". It might be you - I don't know. Just be realistic about the journey that awaits you)
The other thing is to enjoy your time in the field learning and becoming highly skilled in your knowledge and photographic skills ... and always be on the look out for opportunities to show your work.