How to know which slot machine is about to pay

So my experience is that there is no concrete evidence. I already had slots where I didn't win anything for a long time and suddenly I got a huge win. Sometimes you get lucky and something happens in the first few turns. I usually play low stakes at first and then increase the stakes.

I agree with Svenjam, I usually do the same, except that sometimes I start with very high bets at the beginning, but it usually works more the other way around.

No, that is why its called gambling. Sometimes a big win, sometimes a big loss.