31 to 34?

Hi guys, I was just wondering if anyone had any tips (besides grinding practice tests, I’m gonna do that) on how I can raise my 31 to a 34. In particular, does anyone have any prep books that they think would be beneficial to me? I’m taking my next ACT in April.

December ACT:

Composite- 31
English- 33
Reading- 32
Science- 31
Math- 28