I agree with the comments that you need to willing to work with people.
As I am unsure of your age and prior experiences then some of my advice may not suit you.
Firstly some questions you need to think about, your answers to these may steer you to what job your are looking for:
A) Do you want to work with children or adults?
B) Are you willing to work overnight? or are you just wanting a day job.
C) Are you willing wanting a job that you can do an then drive home every night?
D) Do you want to work expeditions or be based at a centre?
E) Are you interested in "Outdoor Recreation" or "Environmental Education". I.e. do you want to share with people a fun sport in nature or do you want to share with others the beauty and importance of nature. If you answer yes to both of these then you perhaps describe yours self as being interested in Outdoors Education.
F) What kind of pay would you be hoping to get? - A bit of a harsh question. If your young then it probably doesn't matter. However, typically Outdoors Guides are rather low paid when compared to the work of a school teach for example.
G) Do you have a partner or family that may be affected by you working expeditions/overnights etc?
H) Are you wanting full time employment or would you like to free lance and work for many companies/schools/organisations doing a variety of trips.
I) Are you interested in any particular pursuits, eg. bushwalking, canoeing, kayaking, rafting, skiiing, climbing etc?.
J) Interested in working in the tourism sector?
Secondly, there are lots of jobs in the Outdoors Industry. If you're motivated and passionate you are bound to get one. A key reason for this is because the working life span of a guide is typically quite short. Subsequently there is a constant turn over of staff and many opportunities to find a job. Reading job ads is a good way to work out what qualifications you think you need to get. Some good places to do this are:
http://www.adventurepro.com.au/outdoorjobs/http://www.voea.vic.edu.au/employment/index.htmlhttp://www.cooeeads.com.au/http://www.oric.org.au/Employment/index.htmhttp://www.tourismalliance.com.au/tourismalliance/index.htmlhttp://www.oeg.net.au/ and
http://www.outwardbound.com.au/ http://www.camps.ymca.org.au(Some of the biggest employers that work with Schools)
Thirdly, there are many full time courses you can do, ranging from 1-4 years. Victoria has the most options:
A) One year courses: TAFE cert III or cert IV in Sport and Outdoor Recreation. Or a post grad Uni Dip in Outdoor Education
B) Two year courses: TAFE cert IV or Diploma in Sport and Outdoor Recreation.
C) Three year course: University degrees with a focus on Outdoor Ed or Rec or Nature or Environmental Studies or Eco tourism etc.
D) Four year courses: Education (School Teaching) degree with a focus on Outdoor Ed or P.E. and Outdoor Ed, (or even just a Dip Ed year after completing a 3 yr degree)
E) Five year courses: It's common for people to do 2 years at TAFE doing a Diploma of Spor & Outdoor Rec. then decide that they want to go to uni to combine it with something else such as a 4 year Outdoor education degree. Often these students can be apply to gain credit for subjects and reduce the 4 years down to 3 or 3.5.
Since your in Melb, some training institutions worth checking out are: Homesglen TAFE, Gordon Institute, Chisholm TAFE, Monash Uni, Latrobe Uni, Ballarat Uni, Vic Uni, Halls Outdoor Education, Mansfield Adult Centre of Education (MACE) and Murrindindi Training Institute (MTI).
Fourthly, other training/employment options are to:
A) To do a traineeship in Sport & Outdoor Recreation, 1 or 2 years in length. There aren't many of these and they aren't well advertised. However essentially you would get paid to work and study a TAFE cert in Sport and Outdoor Rec. A mix of on the job training and and tafe classes/trips etc. A great option as you get to work with people/clients as an assistant instructor
B) Just do short courses in only the specific qualifications that interest you.
Fifthly, some commonly desired/preferred specific quals are:
A) First Aid. If you want to do expeditions then a 7 day Wilderness First Aid course is needed.
B) Light Rigid Drivers Licence. So you can drive a mini bus.
C) Bronze Medalion or Pool Life Guard.
D) Working with Childrens Check
E) Level One flatwater canoeing/kayaking instructor.
My comments are based on my knowledge/experience of the industry. I have been working in the "Outdoors Sector/Industry" since 2006. Mostly only casually as I was studying Education at uni 2007-2010. I am currently full time employed as a Youth Worker/Outdoors instructor doing hiking expeditions of typically about 9 days duration. I do also do residential style programs at a camp. In a standard school term I'll sleep about 20-25 nights where I am responsible for young people. (This is quite a low amount of over night work when compared to expedition Guides that work for other organisations.)
feel free to ask any more specific questions. I hope I was helpful