There are a few factors. For physical it's strength, and for seduction it's charisma. Both are passed against a defensive stat of the enemy (perception and intellect respectfully) and that sets your accuracy and damage bases.
I'll write out what the accuracy base %s should be for clarity.
If your base is:
0 = 50%
10 = 65%
20 = 75%
Though now that you mention it, I wrote these formulas when I first released the game and they do seem a bit low. I've recalculated them for 0.5/0.6 so that they'll have an extra 20% accuracy, making 70% the base. Thank you for pointing it out!