As you have read, there are a lot of different methods of having a toilet that works right. The common thing to all is water. Whether you add it at the start, after you dump, or some at the start and more with each use, you need lots of water. When you dump, if the tank is not 2/3 full, add water. Then after you dump add water. And yes, keep the black tank drain closed unless dumping.
A tank rinser is a good idea. I use a Tornado, others like the Quickie Flush. The Flush King probably works well but uses a lot of water and time. Off course you can always put a hose in the toilet and wash it out, but that can get messy.