ABA is the process of applying interventions systematically from the principles of Behavior Analysis has been used to great effect, and has safely delivered many from their behavioral maladies.
These principles include things like positive reinforcement. When a behavior is followed by a reward, the behavior is more likely to be repeated in the future because of the positive association.
These various techniques can be used in structured situations, like in a classroom or "everyday" situations like family dinnertime, and involve one-on-one interaction between the behavior analyst, caregivers, and the child.