Wander the gallery. Look at the art. Be polite. If you feel able please post some great art :)
I really enjoy the contrast in this piece between the precise Mary and the realistic texture of her clothes and the cherubs looking like jelly babies, along with some odd looking kids. I honestly can't think why they made choices they did.
Self portrait (tempera on board)
Looks like he's missing the top of his skull
Yeah, the eyes are definitely too high - should be centre of the skull. This is early renaissance, I guess they dlhadnt got proportions down yet.
Around that time was the Middle Ages. While paintings were starting to get more realistic (Dark Ages paintings were often pretty much 2D with little attempt at realism) they hadn't rediscovered perspective yet, which happened a century or two later in the Renaissance. Painters were getting really good at fabric & clothing in the Middle Ages but everything else was pretty damn rough.