STeps of Any Hack^_ ^

Greetings, I'm having some issues if it comes to getting into a system / server. I know it's a easy task if the system hasn't been updated for ages and runs old software. But what do you do when you want to hack a person's pc thousand miles away with a updated Linux / windows OS. or maybe a bank website which has real good security and has been updated good. I know in these cases metasploit wont work since the exploits has been updated, (right?) Lets leave out the social engineering part of "Sending a email with a reverse shell in it " . If you could share your experience on how you got into the hardest systems, that be great!

For me this is pure for education purposes since hacking just fascinates me. When i was just 8 years old i wanted to know how people hack that and hacked this, but now that i got the age with me and the dedication / discipline to actually learn it, its gonna be way better and funnier:)