It depends, if you write your own EA then that would eventually become the most reliable method because well, you wrote it.
In other cases if you use someone elses EA or subscribe to a signal, then the reliability is equal to a visit to the casino.
Hello you can find some introductions on Youtube, or you can look for some books as well.
I agree with Anthony. The only other issue with signals other than those who have 500 subscribers are the people who share using cent accounts. A $10,000 loss for you could be $100 loss for them.