1. 50 points per section (M/V) just for being familiar with the test is common for folks in the middle range of scores — say 400-600 per section. The improvements are less at the extremes.
2. Very basic test taking strategies are worth another 20-30 per section for pretty much everyone.
3. Actually study/review of targeted vocab and math will typically yield another 20-100+.
4. I don’t have as much data on this, but I personally think practicing sitting down on a Saturday morning and taking a high stakes test for x-hours in a sterile environment also increases the score 10 points or so. It reduces anxiety at a minimum.
I’ve seen scores go from 10xx-14xx with a 200+ point improvement in both skills over the course is about two months.