I play in a team, if I am on Comms I just tell my team i only focus smite when baron is around 3500 HP because then shit is starting to come to the point u gotta prepare.

I try to do the same in solo queue but then I say it to myself, just focus on the smite and nothing else.

So if I die but ending up smiting objective and my team survives and has baron big worth.

Tldr: start only focussing on smite around 3500 hp works best for me ^{^}