<p>Write a solid essay (10+) and don’t think about it again.
Memorize the 16 grammar rules, and I mean MEMORIZE. Dedicate 5/6 hours in one sitting if that’s how you work, or an hour a day for a couple of weeks if that’s how you roll.</p>
<p>Then it’s just practice from there, shouldn’t take much.
I speak from experience (80/12)</p>