Yeah, the proper way to explore is to save up a ton of turns and then explore 40+ turns all at once. That way you get to keep a high acre/explore for all 40 turns. If you explore in, say, 5 turn increments instead, your acres/explore will drop a few acres each increment, and you'll end up with less acres overall.

As far as army goes, I think the best way for a noob to start out is to explore to 3k acres, maintaining at least 10-20 turrets per acre all along the way. After that, try to maintain a 1:1 ratio of Jets:Turrets. And then try to keep your Troop and Tank numbers equal to 10% of your Jet number. That will give you enough offense to give you some experience attacking at least once per day, but not so much that it encourages topfeeders.

Maintaining a small Troop+Tank count will help give you insurance against griefers, which can be very difficult to deal with when you're a noob. As you get more pro at locating and avoiding griefers, you can decrease your Troops+Tanks in favor of more Jets+Turrets.