Blood for the Baron!

I think for very fine details it's important not to expect one touch of the brush to do it. Use a fine brush and very little paint. eyes. Skull and crossbones etc. can be done with a couple of coats so long as you're brush is good. A blob of paint on a fine brush will just make a mess.

For logos, a good exercise is to restore rubbed logos first. This way you get used to patching up missing bits of the loo before doing them from scratch

As for fine detail and brushes, the brush size makes little difference. It's the point of the brush that's important, the viscosity of the paint (thicker for lighter) and the steadiness of the hand.