Here's a quote from this site:
http://internetcasinolist.com/articles/101102.html
First of all, let's distinguish betting systems from money management. While money management is also unable to guarantee a win, and has no mathematical impact on the game, it's often not a bad idea for a player to use. Money management is a process of limiting or controlling the amount that you bet.
This could take the form of having a stop loss or a stop win number, which means that when you win or loose a certain amount of money, you stop playing. This isn't a bad idea, especially for people who only have a limited amount of money to gamble. Likewise, a stop number can help a person who has a bad habit, like the inability to leave the table. Money management is simply the act of creating a gambling budget and sticking to it. However, like I said, this budget can help you control your finances, but it can not help you win.
Actual betting systems are betting plans. What usually happens is the betting system will talk about "varying your unit bet", which means varying the amount that you bet. They will have various rules, depending on the system. Some will tell you to keep increasing your bets is you win. Others will say keep increasing your bets if you loose. You will also see the exact opposite; decrease when loosing, decrease when winning. Some will want you to hopscotch your bets. Bet five units, followed by three units, followed by 1 unit and then five units again.
Just take a moment to look at these plans. How could any of them make you a winner, or influence the outcome of the game? They can't. How could varying your bet size matter, unless you are counting cards in blackjack? (Or unless you have a budget concern, but remember that is money management). Increasing or decreasing systems play off the fallacy of the "streak", riding it one way or the other.
Imagine this scenario. You are going to bet on a coin flip. You bet tails. The coin toss results in heads. You lost one unit. Should you now double your bet on the next toss? What if heads came out five times in a row? On the sixth toss, should your bet be six times the original? Absolutely not.
On that sixth toss, is tails six times as likely to come out? Once again, absolutely not. Every toss is 50-50. There is no mathematical reason to increase the bet, except in some unwise attempt to "get it all back at once". Now transfer that concept to a casino where you are making bets that are way below 50-50. In fact, the odds are against you instead of even. Does it sound like a good idea to increase your bets? Remember that gambling, except for card counting at blackjack, is a series of independent trials.
There isn't any short cut to gambling success. The few games that are beatable, like blackjack and poker, require lots of knowledge and experience to beat. And no betting system is going to eliminate the house edge built into the other casino games.