You can get a water separator from a store (they are commonly used on air compressors to keep water out of airlines) and hook it up to the hose running to your valve cover.
It's part of your PCV system, one hose draws air in through the intake, and another sucks it out. You will want to put the separator inline with the inlet side of the PCV system, and empty it from time to time.
changing it to a synthetic oil will help it a lot,its not as prone to build up sludge as regular oil is,of course keeping it changed will help also but on some cars in some areas this will happen even if you do run good oil in one,all you can do is regular oil changes and hope it doesn't do it,good luck.