Knowing when a flier is possible can be the difference between a birdie and a bogey or even worse!
The first indicator of whether the shot maybe a flier is the length of the grass your ball is in. If your ball is in taller than normal grass like rough there is a good chance it could be a flier. It only has to be tall enough to be able to get in between your ball and clubface. Another indicator is the wetness of the area around your ball. If enough moisture gets between the ball and the clubface this can also create a flier.
Once you know that the shot may turn into a flier, now you need to know how to compensate for it. A flier is a shot that has less backspin than normal and usually has a lower trajectory. This creates a shot that rolls farther and may land farther also. The best thing to do is to take less club to compensate for the added distance.