Between ages 1 and 2, toddlers can physically do much more than they could before, and that makes slowing down for sleep a drag. Plus, they're learning to test limits (refusing to sleep is one way to do it!).
But toddlers still need daytime downtime, so to help her get some:
Create naptime rituals. A shortened version of your bedtime routine -- say, singing one quick lullaby or telling a brief naptime story, then tucking her in and kissing her -- will help your toddler understand it's time to sleep.
Set the scene. Tell a story starring your child in which she takes a nap, dreams about her favorite toys, and wakes up feeling happy. Your toddler will likely try to sleep just to see if you're right!
Limit distractions. Darken her room and mask sounds that could keep her awake with a white-noise CD or a whirring fan.
Be flexible. While kids this age shouldn't go all day without a nap, switching from two or three naps a day to just one is fine. If your child resists morning naps, don't fight. Just try putting her down again in the afternoon, and she'll probably be a more tired, willing napper.