Most likely, when speaking about gambling, the author means sports betting. If this is really the case, then there are two fundamental approaches to this matter:
1. Try to win a large sum by making small bets over a long period of time (or, as the author put it, try to win gradually).
2. Try to win a large sum by making large and carefully thought-out bets over a relatively short period of time.
It is difficult to say which of these approaches is better. Everything depends on the character and worldview of the individual player. For my part, I can say that for some time now I have begun to lean towards a small number of carefully thought-out bets on large and medium amounts. Simply because it is difficult to find many good bets. Each bet is too unique.