Assassin's Creed Chronicles: India

Every time you pass a checkpoint in AC Chronicles: India, you will be assigned one of three ratings: Shadow, Assassin, or Silencer, depending on your play style.

To achieve an Assassin Gold rating, you must not be seen, and you must kill at least one enemy between checkpoints.

The best area to grind out Gold rankings is in the beginning of Sequence 6. There will be a single guard. Throw a smoke bomb (you cannot kill him otherwise), kill him (I used jump and kill to avoid accidentally triggering a non-lethal takedown), and round the corner until the checkpoint activates. As long as you don't continue climbing past the checkpoint marker, resetting the checkpoint will put you back behind the guard (thanks ShadowStefan for finding this method).