Not sure what level you are on battle classes since you said you don’t play it often. But I would suggest doing your daily roulettes. You will get Gil for it as well as poetics. Look for things that you can buy with your poetics that you can sell on the market board. Also you can do low level treasure maps like if you are level 70 they still give decent Gil. Just have to find people to do it with. If you do those that can net you some Gil. You won’t be rich but you will have Gil to at least buy some stuff on the mb to craft if you don’t want to gather them. Also if you run dungeons and get the armor sets from the dungeons and turn them in to your grand company you can use stuff to buy things from your gc and can sell as well.