Welcome to DV's.

This may not be 100% correct, but if you do reality checks during the day your brain will carry it over into your dream but if you do random checks then the checks in your dreams will be random.

In waking life, do a reality check when you see something out of the ordinary then when you are dreaming and it isn't normal then you brain will think to do a reality check.

Also make sure you keep a DJ, then find your dream sign then do a rc when u see that.