How to know when to increase newborn milk volume

Look out for baby’s cue. This is what I personally did. If you think he still wants more after his usual feeding, make 30ml (first time), gauge how much to increase by his leftovers/when he spits up. However, I’d still recommend to increase 5~10 ml each time. And if he is on bm, don’t have to increase as frequently as fm. My LO was drinking 80~100ml (bm) from 3mo all the way till 8mo. Tried increasing but she won’t finish. As on now (15mo) she’s drinking 210ml.