Here is some more free advice, probably worth what you pay...
First...keep a logbook! Having notes scribbled in the margin might seem boring now, but years later you will treasure the memories of certain sorties and missions. I almost always include my flight members names. So..years later I can recall who flew what interesting missions, etc and it makes for a great trip down memory road. Also...those same stories and insights will be nice to have when you do start prepping for an interview.
Next...suck it up and get your ATP when you get 1200 hours, even if it will be several years before you get out. That will be one less check mark and one less 1000 buck (or more) check to write while you are trying to squirrel away money those last 18 months on active duty. Dabbling into some General Aviation along the way may also kindle an interest in a really neat part of aviation, but even if that's not your bag you'll still be glad you got the ATP early.
Next...make a file NOW of everyone you know who leaves to go to the airlines or reserves/ANG that you have worked for or with. Those contacts may be all the difference in 3 to 5 years.
The advice to charge straight ahead and enjoy the military is spot on...you need to get good at what you are doing NOW before you are any good to the airlines down the road. You will also have a blast doing it--I've already written a few posts on that subject. However, as you make your journey if you'll lift your eyes to that point 3-5 years away every once in a while and start knocking out requirements and keep your logbook and contacts up to date, you'll have a whole lot less frantic backtracking to do when and if you do separate.
And boy oh boy...the ANG was nothing less than a Gift from God to my family during the transition, and to a lot of my bros who were furloughed after 9/11. Even if you think you might want a "clean break", give serious consideration to continuing to serve after your active duty committment is over. I have found the ability to continue to fly, the extra income, and the chance to still don a green bag and rage with the bros every once in a while to all be very satisfying for a variety of reasons. NEVER slam a door behind you when you leave a room...you just might want to walk back in there someday.
Good luck.