Classic progressive betting is a simple and powerful betting strategy. With progressive betting you define yourself a number of "bet levels" and a rule that tells you when to wager a bet pertinent to a certain level. Two specific progressive betting systems are most popular:
"Base two" or "level two" progressive betting system is simple and effective. The point is to bet high on when you keep winning and low when you are losing. You decide on your minimal and maximal bet and simply wager miminum bets after losing and maximal bet after winning. This system is called level two because it only involves two levels of betting and doesn't make any far-going assumptions about what is going to happen next.
"Base five" or "level five" is a little bit more complicated progressive betting system. It is based on 1 - 2 - 3 - 5 - 1 progression which you will understand after reading this explanation. Another popular variant is 1 - 2 - 3 - 6 - 1
As one would expect, base five system is based on five betting levels. You choose your base bet and each level in the progression multiplies the bet. For instance if your base bet is $10 then your bets would be $10, $20, $30, $50 ($60) and then back to $10. As soon as you win a round you progress to the next level. The betting system wraps around itself - that is after you win in level 4 (multiply by five or six) you return back to level 1.
A progressive system like this one makes assumptions about your winning streaks and rewards you accordingly. As an outcome these systems don't work well when your gameplay doesn't have winning streaks, but in reality consistent winning after losting after winning is unlikely. As usually, you must add an element of creativity and see for yourself what is more likely to happen in your games.
Other progressive systems, like Martingale negative progression system or its opposite Paroli positive progression system are similar and manage bets according to specific assumptions the system makes.