Great idea - that's pretty much a perfect strategy for where you're at right now. Learning the major error categories is important, but there are diminishing returns to reviewing the same grammar rules over and over outside the context of the way you'll see questions on the exam.

Like you said, you need to start to better recognize those signals that tell you "check subject verb agreement here" or "this pronoun is going to be important", and if you already know that you're doing a set of 10 pronoun questions you'll not likely have to develop that kind of recognition. Scaffolding your learning that way is helpful up front, but my hunch is that by now your skills are pretty solid, it's the strategy that will take some work - how do you know when to use each rule or to look for that kind of error?

So I'd turn a lot of your emphasis now to doing sets or 10 and 20 question "uncategorized" sets so that you have to see for yourself which rules/errors to employ. That phrasing you had in there about recognizing the comparative word "than" is exactly what you want to do! Then if you realize after a few sets that you struggle noticing a certain type of error (for example, if 4 of the 5 questions you couldn't quite categorize all involved modifiers, you need to go back to a modifier set to think about which clues you're missing) you can go back and work on those in a more focused way.

Love the plan!

if you already know that you're doing a set of 10 pronoun questions you'll not likely have to develop that kind of recognition.

That's exactly what I was thinking.

So I'd turn a lot of your emphasis now to doing sets or 10 and 20 question "uncategorized" sets so that you have to see for yourself which rules/errors to employ.

Okay great - and I actually bought the extra set of GMAT Prep questions for ~ $25, so I can just run some sets of SC questions through that interface. It's amazing how much easier it is to use the POE techniques when you recognize category signal early on in the problem.

Thanks for the comment!