Greetings Downunder! I'm fairly new WitP too. Here's what I posted for another newcomer on a different thread that you might find helpful:
Welcome, as I call it, to the "Land of the Truly Lost" (I was also told that me my soul was now "lost" or "possessed"). Actually, the folks on this forum have been really good to us "newbies" got this game, which by far the most complex and complicated computer game I've ever dealt with. I also do several "war game" board games (I'm a WWI buff, but do others as well), but it's often hard to find opponents in my area to do this with (I live north of Cincinnati).
So where should you start? First, try out the Tutorial. Not only does it address some basic concepts (both from the Allied and Japanese side), but looking at the antimations is a hoot (these include some gigantic air combat/surface combat battles where the opposing ships line up on either side, and have at it). Next, as someone recommended to me, try the Guadacanal scenario (first from the Allied side, then from the Japanese side), with the Historical start setting on; this will give you a feel for what strategies to pursue, how to arrange the various types of TFs, etc. (Later you can turn off the Historical start, and try your own strategy.) Guadalcanal also gives you the variety of "island hopping" (in the Solomons), as well as a significant "land campaign" (New Guinea), plus dealing with both US and British air (and naval) units.
As Canoerebel (aka Dan) advised (he's got a very detailed and interesting AAR post running under Forelorn Hope with John), logistics is a crucial part of WitP. If you don't move supplies/fuel in the direction of you offensives, you're going to be in trouble. Also, you've got to pay attention to support units (SeaBees, aviation, etc.), not just combat units, or your bases, especially those you capture, aren't going to develop as you need them to. You'll also find a bewildering array of naval units that you need to assemble for transport TFs (both to carry and protect those supplies/fuel). I know quite a few of the acronyms for the various naval units, and even I don't know them all; the folks on this forum have been good about explaining some of these nuances.
Which brings me to my next point; don't be afraid to ask questions. The folks on this forum love to help you out. Also, as you start out, don't be afraid to make mistakes (I've only had WitP about a month and have lost plenty of planes/ships with my "goofs") and learning from those mistakes. "Do-overs" are highly recommended, especially as you try out new strategies and tactics, and learn how the WitP "flows." I'm also reading the 200+ page manual (and will probably read it again when I finish), but use it as a resource, and just jump in and have fun (and loads of it). Good luck and good hunting.