I have been using CPAP since 2003, and here are my ideas for cleaning the various bits of kit.
Mask - take the mask into the shower with me every morning, and use a little shower gel around the seal, and inside the mask, rinse off thoroughly. This will ensure that the mask fits snugly, and that all of the oily deposits are washed away, thus curing most of the problems with leaks and slipping.
Hose - take into the shower, and run through with water every day, this should get rid of nasty things which may lurk in there.
Strap - put in the washing machine twice a week (because it can get really "minging") on a "Delicate" setting, and leave to dry out naturally. Do not tumble dry.
Reservoir/humidifier - there has been a lot of talk about whether or not to use distilled water. I never have, and have only had a couple of reservoir failures in six years. I use ordinary tap water, and make sure that the chamber is filled to the midway mark every night. I now clean the chamber every day, with boiling water. I used to use vinegar, but I am not sure what the long term effects are, and I once forgot to rinse out the chamber, and that was not very pleasant the next day. I now use the following method:
Once a week, crumble up a small (1cm) piece of dishwasher tablet, and put it in the chamber. Fill to the neck with boiling water, and leave for a couple of hours. This will dissolve all traces of lime scale, and leave the chamber sparkling. DO REMEMBER TO RINSE OUT THOROUGHLY (FIVE OR SIX TIMES AT LEAST, WHILST AGITATING) IF YOU USE THIS METHOD.
I also use an old paintbrush to remove dust from the CPAP machine, and check the condition of the filter on a weekly basis.
This piece of kit is the most important thing to OSA sufferers, so we need to maintain it in order to get the best from it.