The most efficient and basic skills for football is to dribble the ball, keeping it in possession. Run with the ball, is not as simple as it sounds, it needs good control, balance, coordination. To get a grab on it, move up and down the pitch with the ball in possession and maintain your control.
NFL games are divided into four 15-minute quarters, separated by a 12-minute break at halftime. Each offensive team has 40 seconds from the end of a given play until they must snap of the ball for the start of the next play, otherwise they will be penalized for delay of game.