Your Wealth income will be greatly increased by just operating a few Mines, thus there is little need to build as many Markets and/or Caravans as you would have to with other nations.
The Incan player's Wealth income enables them to build Universities and train a lot of Scholars early on, allowing them to gain a technological advantage.
Remember you can use your increased Wealth income to trade resources at the Market.
Press the enemy with units constantly, this way they will be in a difficult situation and you will get a 25% refund on your lost units helping you to continue the cycle of pressing.