Many snooker and pool players struggle when using the test and try to avoid it by using extensions but you need to become comfortable with it if your going to compete against the better players.
Some of the major mistakes are cramping your cue action and not addressing the cue ball. The most important part is keeping the cue as low as you can to the rest ( not elevated ) and delivering the cue through smoothly like your normal cue action. Other aspects are keeping the elbow parallel to the table.
Need some coaching and your in Sydney give me a call this is one area im very good at!