Between short stories and novels, the Amaranthine series is pretty expansive. Though you can read them in any order you want, here is what I'd recommend:
1. Book 1: Shades of Gray 2. Book 2: Legacy of Ghosts 3.Vampire Morsels Short Story Collection 4. Book 3: Ties of Blood 5. Book 4: Ashes of Deceit 6.Heart of the Raven Mini-Prologue Collection 7. Book 5: Heart of the Raven 8.Tales from the Island: Six Short Stories 9. Book 6: Children of Shadows 10: Book 7: Clash of Legends 11:Patrick's Story: Brothers of Darkness 12: Road to Darkness short story 13:Thirteen Guests Short Story Collection 14: Book 8: Masque of the Vampire 15: Book 9: Goddess of Night 16:Tales of the Executioners 17:Honeymoon Havoc Short Story 18:A Different Time Short Story 19:Deal with the Devil: Jorick's Origin available in Creature Feature Anthology