Aiite thank you guys. I guess ill use autocracy and tradition (not too fond bout wasting 2 of policy slots cause i usually dont run autocracy nor tradition) Yeah I understand that a spear is less complicated then a tank, but is unit maintenance going to keep on rising forever?
Commerce is often better for gold then Tradition if you'd prefer that. Also, consider selling off some buildings that you aren't using. Not every city needs an Armory and a Forge, for instance.
Make sure you're selling off your excess luxuries for gold, this will generate a lot. Try to keep your trade routes to no more then 3-5 roads. If it takes more then 3 road hexes, a Harbor is better if possible.
Try to get your capital population as high as possible too. Every time your capital grows, each of your trade routes gains 0.15 gold. If you have a lot of cities, which you probably do since you're building lots of troops, then that can be a huge boost.
Finally, next patch, gold should be easier to come by. You'll get free gold every time you kill a unit if you fill out the honor tree, 10% more gold in every city that has a temple if you Piety-->Theocracy, +1 gold from each specialist from finishing Commerce,
8 Maintanence free units from Free Speech (this one is directly relevant to your question) +1 Gold from each science building from finishing Rationalism, a lot of the buildings had their gold costs reduced, and some of the wonders now give +gold per turn on top of their old bonuses.