If you cutting your kids hair at home, always use professional hair cutting scissors to produce clean cut otherwise with most other scissors, your child's hair will be broken at ends and this will result in split ends and bad shape.
Most of the times parents decide to trim their children's bangs by themselves and although it may appear as a simple task, cutting a clean and straight line is not always easy. The best way is to cut the hair when it's wet but since wet hair stretch longer it is also easy to cut too much off. On the other hand, cutting dry hair is much easier but it's more difficult to get the hair strands under scissor to create a straight clean cut.