Be sure to follow a short bed time routine for your toddler. This will train them to go to sleep by themselves. If they are used to going to sleep without you near them, or holding them, then it will be easier for them to get back to sleep after a late night disturbance in their sleep pattern.
Between 18 and 24 months, your toddler might start climbing out of their crib. This can cause serious injury. You should make it more difficult for them to get out, by lowering the mattress height and removing stuffed toys that they can use as stepping platforms.
If your child still persists in climbing out, consider buying a cover for their crib, or moving them onto a bed or mattress on the floor. Beds can be fitted with safety slats to prevent accidental falls during the child's sleep. It will take a night or two to get your child used to the new sleeping arrangements and the novelty will wear off, allowing them to establish new sleeping habits.