Gambling systems: blackjack, slot machines

I would like to know if any one has a gambling strategy, for any type of game, like video poker or even slots. Is it really working for you?
Perhaps you know about a book that I can learn good system.
I would appreciate it. Thank you.

This is one way to do it, for blackjack:
If I'm under 15 I always hit. I never won when I didn't hit. So that is my system now.

I can tell you about some systems I use while playing, but you have to know it is not always effective.
For playing slots just cross your fingers and make a wish…

I use no system.
I found out that my first instinct is usually the best one.
If I try to think and over think, I usually make the wrong decision.

In the literature there are really elaborate strategies on the question of "How to beat slot machines".
First thing is to play low and keep track of how many times the machine pays twice your bet or better.
Second, you have to count how many times the machine spins between these wins.
You do this several times, and then average the number of spins between the wins. Then you bet low for that many times and then start betting high until you get another win.

O.K.
That is good, but I have no patience to try it out.
It'll be interesting to try it on an online slot for fun money and see how well it works.