Trees

Shortly into veging, the plant will produce pre flowers right at the nodes. The crevice of the stalk and branch. Calyxes typically will be attached to that spot right at their base. Pollen sacs will typically have a short stem off the base that then connects it the node. If you look up some pics of male plants, you will see their pollen sacs kind of hanging in bunches from little stems, same thing happens with the pre flowers, but you usually only get 1 or 2 sacs at the node as opposed to like a dozen.

Thats about where my experience with males and herms end. In my experience though, it mostly just comes down to the shape of the part. Round convex shape, almost certainly male part. Tear drop concave shape, female part.

With experience you will be able to sex the plants earlier and earlier.

Hope that helps. Good luck.