Nice short article on “How to Make Non-Player Characters That Your players Will Like” – good advice for DMs from www.DMDave.com.
Specifically liked the following quote from the article…
‘…In a situation where a PC might know someone able to help the party, their player can declare, ‘I know a guy.’ The player invents the NPC, sketching the guy’s background and relationship to the PC. (This rule assumes the gender-neutral usage of ‘guy.’) Now the party can reach out to the new character. To determine the NPC’s reaction, the player who created the guy makes a Charisma check. … found this simple and very loose mechanic invites players to create critical NPCs and continue developing (revealing) backstory as they play.’