I'm a professional and have been for twenty years. My website is here so you can see what I'm talking about www.rodedwards.co.uk
The first thought that came into my head when i read your post was "Oh no ... not another one ..!"
I really don't wish to rain on your parade, but sadly, since the advent of digital imagery (and the internet), photography and in particular landscape photography has lost most of its commercial value. The market is flooded with very competent amateur photographers who are happy to supply their images to clients and publishers etc for little or no return. This has made it practically impossible for professionals to earn a living from just landscape photography.
If your work is exceptionally good and unique, there is always room for the best but if your work is not better than 99% of other professional photographers you will maybe make some beer money but undoubtably fail to earn a realistic living from just shooting landscapes. This is certainly true for us over in the UK and Europe but the USA market is bigger and perhaps very slightly more buoyant. Check out Peter Lik (www.lik.com
), he is an Ozzie in USA and an expert in marketing his work.
In answer to your questions :
1 ) Hard work. Get an amazing portfolio together, market yourself and haul it around to your potential clients. Academic qualifications are irrelevant as no client cares if you've been to university - they only care about the photo.
2 ) It will happen slowly ... you need a lucky break. I'm still waiting for mine.
3 ) I only use Canon gear (4 x 22mp full frame dslrs). It's more than adequate for 99% of commercial uses. A few years ago I even had 12MP images cropped to panoramic (6mp) and blown up to massive 24 sheet posters in the London Underground. More megapixels are great but most clients won't notice or care. They just want cheap, high quality images.
In closing ... I'm really not trying to put you off from trying to become pro, but you need to think long and hard before giving up a secure job with a stable income. It's harder now that its EVER been to earn a living from just landscape photography so prepare for a life dedicated to photography. If you can pull it off fantastic, well done I have the greatest respect and will admire your work. My advice is keep the day job and when (or if) you start to earn good money then turn pro ... but don't expect it to happen overnight or over a couple of years.
Best of luck and just enjoy taking great pics ...