In modern English, the following is rarely used, though it has some local or regional currency:
Mr John
and the following is probably never used:
Mr Smith John
while these two forms are pretty much identical in usage:
Mr Smith
Mr John Smith
(although if addressing someone directly, or in the salutation of a letter, "Mr Smith" is preferred).
If you want to use the entire name then you always put the first name before the surname. (The excepion would be in an index or filing system, but here you probably wouldn't include the title "Mr", and if you did include it, it would go before the first name: "Smith, Mr John".)
It's true that you call someone "Mr Smith" in a formal situation, and that if you know them well you just call them by their first name ("John") - without any title. But in fact, you don't even have to know them well. Usually when people meet at a social occasion or gain a new work colleague they begin on first-name terms right from the start. This wasn't the case a hundred or even fifty years ago, but has been a strong trend over the last few decades.
The titles "Mrs" and "Ms" work the same way. The titles "Master" and "Miss" may occasionally be used with first names alone, but this usage is considered old-fashioned except in the southern US.
"Sir", on the other hand, if used as a title for a knight (rather than without a name as a polite way of addressing any male), comes before the first name (or sometimes the full name), not the surname: "Sir John Smith" or "Sir John", not "Sir Smith".
Spelling-wise, "Mr", "Mrs", "Ms" and "Dr" are almost always written without full stops in BrE, and with full stops in AmE ("Mr.", "Mrs.", etc). "Miss", "Master", "Sir" are written without full stops in both BrE and AmE.