early on, i taught my dog the "sit" command. that thing works for everything. she runs away, SIT and you walk over and get her. she's dashing for a dropped chocolate bar, SIT and you pick that candy up. she's jumping all over someone, SIT and they'll get a nice pat on the head instead (unless it's a total stranger and she flips out, hard to calm down pure instinct immediately). she starts to growl at a dog on a walk, SIT and she doesn't go anywhere until that dog is gone.
an obedience command can be a comforting thing for a dog - someone else can call the shots (me) instead of the dog feeling like it has to defend itself or be the alpha in a stressful situation. a SIT is never a punish, it's a "listen up" thing, the closest you'll get to a "time out" for a dog. for a kid, the time out comes with explanations as well as a cooling off period, but a dog doesn't understand your explanations - just tell her to SIT and chill until she can go about her normal business.
SIT also means treats when she's especially good, or at least a pat on the head and praise. positive reinforcement.