If by 'best' you mean easiest, just ride back and forth near the front of the day care (a step in front of the twins), going left and right. This requires relatively little brain power, and if you're breeding for multiple eggs, the daycare man will let you know each time he has another egg as long as you don't have a full party (probably intentionally programed in so as not to harass a player with a full team of eggs).