My three year old daughter has stopped taking her afternoon nap. How do I get her back to the routine?

Wake her up earlier in the morning and get her to use up her energy with some activities. Probably can exercise or do some physical activities before the desired nap timing then have a shower to unwind and nap. Not all toddlers need an afternoon nap and do be prepared that introducing an afternoon nap may lead to a later bedtime as well.