So you grab a normal shield. you time your block to stagger and go on the attack. You take WAY less damage and you get a chance to get a few free attacks in.

in the early game I find a fully upgraded spear is good for this. I took on a 2 star Skeleton this way with a upgraded wooden shield and Flint spear. (Jerk showed up only after a large group left me low... so he killed me first. (first death on the new toon) and I was able to grab my stuff, gear up. eat some honey, and deer meat and then went back in and just put him down.

If you just hold block you do take less damage but you don't stagger and take more than you did if you block right.

I've always seen the tower shield as kinda pointless.