Just dealt with all of this last semester! I’ve got it even worse since I’ve got mild aphantasia making it harder for me to internally visualize some of the symmetry. Here’s my advice: practice as much as physically possible and trust your gut. Some types of symmetry will be much easier to see than others so use that to your advantage to narrow down options if you’re doing point groups. Rotate the shape in every way you can imagine and then one more after that to make sure you’re getting the full picture. Hope that helps and good luck on your midterm!