Black has run out with one back checker, been pointed on by a set of double fives, and compounded his problems by staying on the bar. White is well placed to make his own four point, putting two of Black's checkers on the bar. In a few moves' time, Black will still have two checkers on the bar and White a completely closed board. The end result will be that White wins a gammon.
The strategies are clear. White should keep hitting Black whenever he can; quite often he will have to leave a blot in his home board to do so. For example, if White rolls 6-1 in the above position he should play 10/4*; 8/7. Making the bar-point with 13/7, 8/7 would be completely the wrong idea. If he cannot hit, White should bring more checkers closer to the action, ready to hit next time. He should not worry about his back checkers; there will be plenty of time to escape those later. Black, meanwhile, just has to hope to make an anchor. Having made it he should not give it up prematurely, but must patiently build up a strong home board, ready to contain a later hit white checker.
Doubling strategy must be learnt through experience. As soon as White sees a good chance of a gammon he should think of doubling. The above position is a double and a very big pass. If White's checkers on his nine and 10 points were both back on his mid-point he would still have a double, although Black would now have a bare take. For Black to take he must have a realistic chance of making an anchor, and it also helps if he has strengths of his own - having made his own five point, for example. One final piece of advice: the defending side tends to be over-optimistic about its chances of making an anchor - if in doubt, drop a double. Gammons are expensive!