Wanted to bump this to the top.
Never know who may be visiting as a guest for the first time, looking for information, and interested in learning some of the basics.
For myself, getting the feel of the sanding process was and still is key to successful cabbing.
The only thing I might add to the above posts is knowing when to consider to change out to new abrasives. I am still using silicon carbide. Have not made the important change over to diamond yet.
Seth has mentioned several times the importance of using diamond. My immediate realistic goal is to purchase something like one of the Gennie units. After working with Ralphs one day, it became apparent the importance of having that type of set up if a person is going to make this a long term hobby or business.
Don't get me wrong..... Just starting out, there is absolutely nothing at all wrong with the silicon carbide abrasives. I still continue to be able to turn out some nice cabs. It is the ease of the process that is increased when using a set up like one of the Genies that I look forward too enjoying on a daily basis.
So for now....., using silicon carbide abrasives can be a combination of using a new 100 grit belt as a 100 grit belt. Then finding ourselves using it in place of something like a 220 grit when it becomes somewhat worn. Same thing with a 220. I will use it as a 220 when new, and then find myself using it like I might a newer 400 or even a 600 grit belt as it becomes worn.
Agates are a big indicator for me as to when it is time to change into a new belt.
As the guide above explains..... Always watching the progress of the removal of sanding scratches. After a short time it began to be second nature what to expect the surface of a stone to look like when finishing the 100 grit. Knowing that it was completely ready to move on to the next finer grit, and so on just prior to polishing.
Remembering all along not to use a lot of pressure. Letting each of the abrasives do their own thing.
The same is true if using silicon carbide or diamond. Maybe more so with diamond in regards to remembering to let the abrasive do the work. Diamond will only grind or polish in accordance to it's individual abrasive grit. Not pressure. Especially not pressure....
Any hooo...... just wanted to bring this topic to the forefront again. For me, getting a handle on the sanding process was the most important thing. Once I started to understand it, and actually get a feel for it, the processes become clearer and easier. The results were less aggravation and less time spent returning to previous grits two and three times .

Maybe others would like to add their experiences here as well, and or correct me on any of the above as I am in fact still very new and still learning...