It depends on the person My D19 did no more than a couple of practice tests between her tests and her scores increased by 250 points between her first PSAT 10 and her SATs, mostly from doing PSAT 10 twice, and the PSAT/NMSQT. It was about focusing on her studies a lot more, increased maturity, and mostly about the classes that she took between the tests.
Between the first PSAT 10 and the PSAT/NMSQT she finished pre-calc and Honors English with an absolutely amazing teacher (increase of 180 pts). Between then and the SAT, she finished a creative writing workshop over the summer, the first semesters of AP Calc BC and of AP English Lit.