Always use fertiilizers that contain Copper, and occasionally spray the tree with Copper. One of the functions of Copper is to lignify trunk and branches (and presumably bark). Branches will be less likely to be lanky or droopy.
I have also heard a claim that bark splitting can be a sign of Copper deficiency. I don't know that at all for sure, but one Carrie mango, with multiple deep wide splits showing the wood, healed up quickly after I sprayed it several times with Liquid Copper.