The basic decision to be made in Pai Gow is how to arrange one’s hands. Given any four tiles, there are always three ways to arrange them into two hands (although some arrangements may be functionally identical to others). Sometimes one way will be clearly superior to another, but at other times it is difficult to determine the best strategy.
There are three ways to arrange these tiles into two hands. One of these ways is very unwise.
For instance, consider the four tiles at right. It would clearly be unwise to combine tile A with tile B, since each hand would be worth zero. It would make more sense to combine tile A with tile C, in which case both hands would be worth 5. Or you could pair tile A with tile D, in which case your front hand would be worth 3 and your rear hand would be worth 7. Which is a better choice?
If you think the dealer will have poor hands, such as a front of 1 and a rear of 6, you would want to pair tile A with tile D in order to maximize your chance of winning. If you are afraid the dealer may have a better hand, such as a front of 4 and a rear of 9, then you will want to pair tile A with tile C in order to maximize your chance of pushing. You might also consider that pairing tile A with tile D will make it more likely that a tie would break in your favor.
Experience will help a player get a feel for which hand combinations will work well in which situations. Many players use various superstitions as well, believing that one should (for instance) never pair a 6-4 tile with a nine.