What doesn't help
I will say I'm pretty certain will not help my grappling. Avoiding it. For one thing, taking several "leaves of absence" from budo over the years has not helped my progress (there are many that started at the same time as me or even after have long since passed me by).
But for another, it's become easy to just keep working of nage waza during class, especially if we happen to get involved in an interesting aspect of the subject. For a time, I was running a noon class twice a week, and since I was in charge, that was particularly easy to do. Basically, I've avoided it because I didn't like it.
The answer is the same, of course. Keep doing it, keep doing it.