How can you get the best out of treatment?
First, please be honest with your therapist about your successes and failures. There may be a temptation to hide any failures in the programme, but this will not help. It is perfectly normal for things to be difficult sometimes, but your therapist needs to know what is happening to be able to help you. 'Failures' may actually have a positive value in helping us to learn more about the problems and be better prepared for future difficulties. Second, please don't hide embarrassing or unpleasant thoughts. By definition, many obsessional thoughts are unpleasant or silly, but your therapist will not be shocked or offended by them. Many other people have had the same thoughts.
Third, try to be strict with yourself in deciding whether behaviour is obsessional or not. Often the best rule is to assume it~s obsessional until you both agree that it is not! This may apply particularly to asking for reassurance. It can be very hard not to get reassurance but it is important that you learn to cope, without depending too much on your family or friends. They can help by supporting your efforts, but not by reassuring you, or by helping you to perform rituals.
Finally, it can be very helpful to have a plan for what to do if you do slip up and perform some rituals. Often the best plan is to deliberately undo' the ritual. For instance, if you wash when you shouldn't have, go back and deliberately touch something 'dirty'. Your therapist can help you work out a plan which will be helpful for you.