Throughout the history of online casinos, some people have claimed to discover a gambling formulas to beat online roulette. For many years these betting systems have been "re-discovered" and tested-and many of them hold no substance what so ever. A lot of these betting formulas came from names like Fibonacci, Martingale, D'Alembert and Labouchere. But one formula that does hold substance is the one where it involves increasing your bets as you lose-primarily on the even money wagers like red or black.
Martingale is keyed to doubling your wager after each loss until you finally win. When you do win, you will only be one unit ahead. When it comes to D'Alembert, it is a technique related to increasing one unit of wager each time you lose and cutting back a unit when you win.
Whatever the system, you must be prepared to use sums of your bankroll to win one single unit. Slow, but it can work. You will hear of others like the Reverse Labouchere (also called the Reverse Labby), where you will be increasing your bets continually until you reach the house limit. In modern times, players have searched for "biased wheels" where some defect in the wheel itself creates an edge because the ball seems to fall in a certain "sector" more often than it should on a random basis. This apparent bias allows an edge to alert players and most modern casinos are well aware of disastrous consequences of using a biased wheel and constantly guard against it. Most casinos allow players to track the results of the game on cards they offer. Some strategies involve patterns of odd/even, red/black, sections or rows or just repeating numbers. However you play, always bet with your head, not your heart.