Honestly, with +2 damage on your melee attacks, you’ll have fewer enemies to worry about as you murder their faces. That’s the best defense.
Using the AI against itself, you should be able to avoid getting attacked to often (in theory, if you are playing with two characters that might be tougher, not sure - I am used to threre being 2 other figures that can absorb some hits for me), and don’t forget to use your items to mitigate damage (like a healing potion) or inflicting poison (dagger).
Mild spoiler for a skill option at level 5 - skills aren’t behind sealed envelopes so I don’t consider them sacred, but some folks like to be surprised by what they can get when they level up, so spoiler JIC.
And then you can unlock a skill at level 5 that allows you to have two augments up at once, and then you can do poison, muddle, and +2 damage at once (that’s what I’m running right now). I only just unlocked that so I don’t know how viable it actually is (you have to have 3 cards set up in your active area, which means only have 7 to play at max, but the good news is they aren’t lost from active so they are considered in your discard pile and can therefor be picked back up after a rest or by drinking a stamina potion, so in theory it shouldn’t hurt too bad.