Be sure to watch your diplo screen for 20 turn deals. All gpt, lux per turn, and peace treaties last 20 turns. If you break a per turn deal (of any sort, I think), you'll never be able to trade for anything with a per turn deal on your side again. That forces you to make lump sum or tech deals from there on out. No outgoing gpt, no outgoing resources. And I can't recall a single game in which I was ever able to repair my trade rep. BTDT, it hurt.
As far as being militaristic, did you build a barracks? If not, your warriors are just like everyone else's. Mil just means that barracks cost 20 shields instead of 40. If you have no horses or iron, you'll have to rely on archers, cats and spears. It may be helpful to fight a defensive war for a little while. Figure out where the AI wants to send troops (they'll send to the same place over and over), try to put a town on a hill, build a wall and barracks, and pile a bunch of spears, archers and cats in there. The hill and the wall with improve defenses, the barracks will heal everyone. Use the cats to soften them up, and the archers to kill them.
ETA: Regarding unit experience:
Conscripts - 2 HP
Regulars - 3 HP
Veterans - 4 HP
Elites - 5 HP
Any unit can be promoted by winning a battle. Elites can get you an MGL, which can be used to build an army or (if my memory is correct) a small wonder. If you build an army, you must then load it with 3 (or 4, if you've built The Pentagon) units. Load all of the same type in it, or you risk losing some potential movement. For example, a knight army is a 3-move unit. An army with 2 knights and a swordsman is a 2 move-unit because of the sword. (And anyone who knows me to be wrong in this is free to correct me.)
ETA 2: When Elites get an MGL, they promote to Elite*. I don't think they get an extra HP for that, and they can no longer get another MGL. I think (and my memory is fuzzy here) that if you then upgrade an Elite*, they'll go back to veteran and become eligible for promotion and from there, another MGL. Again, someone please correct me if I'm wrong.
SGLs can be used to build Great Wonders. Don't use the "Scientific Golden Age." It's bugged, unless they've fixed that since I've been away, which seems unlikely.