Don't see anything mindblowingly brilliant about this technique. I mean mostly that is how we approach SC, by doing splits. The problem if you ask me is more not being able to figure out which error to look for or how to identify which of the 7-8 error types is tested in a sentence. At least on high difficulty questions that is what I've found to a problem and practicing a lot of questions definitely helps as suggested by carcass.
Here's how I got a 760 on the GMAT