It is possible that you are quite good at analyzing but there is also a possibility that previously you were nothing more than lucky, you can evaluate what you analyzed in the previous bet that led you to victory, if you find that the analysis you did really had a big contribution in achieving the previous victory then you can do the same thing on the next bet, but one thing I will suggest is to make sure that you only bet using a small amount, an amount that you can afford to lose, because of course gambling is still gambling.
You are right mate, even if he is not good in making accurate prediction, he should still not forget that gambling can always bring an uncertain result especially when you don't expect the result. He should also make sure to always use his strategy to be able to always make more accurate prediction. If he is too overconfident or cultivate the attitude of pride, he might not be able to do the predictions as accurate as before.
Then I can also add, we know that there is no accurate prediction. But what is sad is that even though they know that the prediction is not accurate, they assumed that the analysis of their prediction was correct and that is the problem for them.
Although, it is not bad to have confidence but of course make sure that what we are giving confidence to is really right so that we will not be happy with what we give such things.