Suggest that she be using the potty herself. About every hour or so, ask him to feel his diaper to see if it is wet or nice and dry. Reward him with a small treat for any successes on the potty. Read children's books about potty training. I know some parents argue that girls are easier to train than boys.
Girls tend to train sooner than boys.
Also children with easy temperaments train sooner because they're eager to please their parents. Some children are distractable and impulsive and need more guidance from their parents to successfully use the potty. Every child is different, I know, but the daycare centers don't seem to care. Our center made it mandatory to have all toddlers potty trained by the time they entered the 3 year old class or else they won't promote them. Now I have my youngest in a home environment and at 18 mos, wants to try to potty.