Here is what to do if the effectiveness falls off a cliff. You can use the positive bet selection that is currently failing and bet the opposite.
You can also look for the absence of characteristics. You then deduce what would happen if a certain condition where not to exist and that that feature of it not existing were to also continue. For instance, there could be chaos in the red & blacks. So you could ask yourself if there was an absence of consistent singles as well as an absence of consistent repeats then what would happen next if that were to continue. It's possible to follow the absence of characteristics.
You can also look for the absence of characteristics. You then deduce what would happen if a certain condition where not to exist and that that feature of it not existing were to also continue. For instance, there could be chaos in the red & blacks. So you could ask yourself if there was an absence of consistent singles as well as an absence of consistent repeats then what would happen next if that were to continue. It's possible to follow the absence of characteristics.