How can I get a dryad in my village?
I already build new home for her but nothing happens.I have 18 gold(if that matters) but no one moves into the new home. In my village I already have 4 NPCs.
For the dryad to move in, you must have killed at least one boss (Eye of Cthulhu, Eater of Worlds, Brain of Cthulhu, or Skeletron). (see the wiki page for more information)
Eye of Cthulhu is the easiest. If you want to fight him now, bring 6 lenses to a Demon Altar or Crimson Altar, craft a Suspicious Looking Eye, and use it at night.