My dd has been in OT for two years now. One hour per week. This has been the most important part of dd's therapy, in my opinion. Some weeks it seems as if they don't do much, but the OT really gives me pointers on what to do at home. At the appt, dd does many different things. They start every appt with swinging. When dd started OT, her sensory profile included extreme proprioceptive disturbance as well as vestibular problems, on top of fine motor issues and poor muscle tone, poor tracking and other motor issues. While she still has these issues, they are greatly improved. When dd started OT two years ago she would swing on the swing and never became dizzy (underresponsive Vestibular processing). She now has better vestibular processing. DD has modulation issues that have been hard to address-she can be underresponsive sometimes and overresponsive other times. The OT works hard to develop appropriate sensory modulation. This happens through controlled sensory exposure over time. DD does still have over and under responsiveness but things have gotten much better. When she started she could not tap out a beat with her fingers, now they are working on tandem (two hands in sync) tapping and dd is doing quite well.
In your post you talked about planning and carrying out...I believe this is the proprioceptive piece. They have trouble with their body in relation to other things, like the floor they're walking on, the paper they're trying to write on, the door they try to shut, etc, etc. It takes a long time to modulate and correct the problems, but for us, these corrections have been so worthwhile.
Also, we began the Wilbarger Brushing Protocol, and this helped dd with her modulation issues. She will now ask to be brushed. I don't know why it works but it does, giving stimulation to the sensory system, much like Temple Grandin's squeeze machine. Sensory stimulation can be very comforting, calming, and helps re-set the over functioning sensory responsiveness (this is why so many of these kids self stim, I believe).
Another area where dd has had tremendous help is in fine motor skills. When she started OT, at almost age 5 she could not trace a circle nor cut with scissors. She is almost on grade level now and while she will probably have handwriting issues (due to the fine motor and proprioceptive issues) she is doing quite well. Our OT put DD through Handwriting Without Tears, which was a very good program.
I also have a dd with overwhelming anxiety issues. While OT has helped with them somewhat, I am finding for my dd, the anxiety is just as much social confusion and lack of understanding of what's going on around her as much as the sensory piece. While we have done quite well addressing the sensory piece, the social anxiety, emotional volatility and poor affect regulation are what I am needing to deal with now that the sensory piece is being addressed. So I am bringing this up just to relay that treating the sensory piece does not by itself cure the anxiety, there is still a need to teach age appropriate coping mechanisms and social skills. Only time will be able to develop my dd's ability to understand the proper give and take of interacting with peers without leaving her feeling overwhelmed.
Good luck.