taxes

taxes are based on loyalty that you build up on your colonies, you must have a high housing to increase your population count if you are going to be a tax based empire, aminer is naturaly good at mining which certain missions will increasing your mining research. and also consumer goods are a natural produce from aminer.
take into consideration that market prices will rise and fall and if you increase your population you also increase your pr level

Its a little like this
Tax Miner; Food has to be below 39 with Consumer Goods.
750+ land, make up to two c2s, loyalty up them first to 5000,because if you build the housing first then loyalty up you pay for however many people to loyalty vs doing it first and only paying 1/1000 of what it would probably cost if you full built housing and fully populated and only to start rewarding

The food part is extremely important. Otherwise, your pop will DIE

> tax miner: research housing,
build housing on all your planets,
reward popluation to rise loyalty,
ensure that the amount of land each planet has is more than 600 otherwise its a waste of ores,
ensure that you have enough food to support your populations and have consumer goods to have a good income .

hope it helped you