Dinraal, Naydra and Farosh

Dinraal is fire, and the route runs around the Eldin mountains and the north. Naydra is ice, on Lanayru after you free it. Farosh is electricity, over the Faron lakes and the Bridge of Hylia area. Horns are the piece armor upgrades ask for most often. Fangs, claws and scales are the rest of the set. Shoot the part you still need, not the closest glowing spot.

The body itself punishes you if you crash into it. Dinraal burns, Naydra freezes, Farosh shocks, and the spikes they shed can hit the ground you are standing on. Use an updraft or a high ledge, enter bullet time, and loose one careful arrow. Spamming the bow on one pass does not drop extra parts. Wait for the next loop.

Naydra starts at the Spring of Wisdom, wrapped in Malice eyes. You cannot farm parts until those eyes are shot off and the dragon is calm. Follow it up the mountain, break each eye, and watch the pools. After the spring accepts it, Naydra flies a normal route and the part drops work like the other two.

A campfire until morning is the usual way to meet a dragon at a spot you have already marked. They are not on a blood-moon timer in the way monsters are. If the part you shot fell into water or off a cliff, the drop is still there. Pin it and climb down. Great Fairies will ask for a horn long before you are done with the rest of the armor list.