When at a craps table I try to pay attention to the flow of numbers from the dice, as occasionally the dice will produce some unusual sequences of numbers. Sequences that are well within the standard distribution of numbers obtainable from two dice but unusual in that these sequences occur infrequently. What might be causing these unusual sequences is of little concern to me, they do happen. The strategy is simple. If the hard way numbers appear more frequently than usual you place a bet on all the hard ways. The amount is immaterial as long as you have the bankroll to sustain the bets. Hardway bets that lose because of easy way rolls are replaced until the shooter sevens out. Hits of the hardway numbers are parlayed 3 times before taking a profit. I.e., a $1 hard six becomes a $10 hard six which becomes a $100 hard six which becomes a $1000 hard six on the third consecutive hard way rolled. On the third hard way you drag $800 and shoot $200 on the hard way. Doesn't happen very often but if you start small and hit a table where the hard ways are jumping around like crazy it can be a lot of fun.
I've hit the 4 hard way bet on two different occasions and the 3 bet parley a good many times. If the hard ways are not hitting you lay off them and use whatever betting scheme you normally use.
By being selective in when to bet the hard ways it keeps you from betting them when the dice are not passing as well as when the dice are chopping. I've used a similar parlay-betting scheme to bet the horn on come out rolls and have hit 3 number parlays numerous times. The payoff is not as good as with the hard ways though.
I realize that these bets pay a tremendous percentage to the house and don't make them all the time, but sometimes they help spice up the action in a frequently boring and frustrating game.