Get a cat.
If you can't get a cat get the landlord to deal with it if it's up to him/her.
If up to you read below:
Poison will result in 2 weeks of funky smells you can't find the source of.
I've had the second best luck with sticky traps with small mice as sometimes they have picky tastes. (best with cats, but the healthy one died last year and the current one is 18 years old and going senile)
Remove all sources of water and food if possible.
Place traps along walls and the most likely high traffic areas, for snap traps place the trigger end pointing at the wall.
I have had no luck with live traps.
If all else fails hire a professional exterminator.
-edit-
If it's rats, you got a bigger problem. Took a month to get one that was living in my basement, it would lick the penut butter off the trigger of the traps, had to resort to poison, found one stiff and smelly rat a week later.
You can tell if it's a rat if it has droppings almost the size of a peanuts (not the shells), mice leave droppings the size of a grain of rice.
Also wear a good dust mask when cleaning up rodent droppings because you can get serious diseases from the dust created when disturbing dry droppings.
-edit-