At age 2, most children will have a favourite show. This is the time to begin setting limits on the amount of time spent in front of the TV. Most experts agree that one hour per day is adequate for a 2 year old.
You should select shows that are educational, and that have lots of colours and sounds. Programs that engage the child are best.
You definitely want to stay away from any shows that are violent. Studies have shown that children who are allowed to watch violent programs will show aggression more easily.
Make sure that your toddler knows the limits. Tell her more than once, that she can only watch until her show is over and then the TV will be shut off. It also helps if you give your toddler a warning a few minutes before the show is about to end. Then she will be ready to move on to another activity.