Start by losing weight in large chunks, because the price goes way up when losing weight in small amounts.
Wheels, fuel tank, battery, exhaust will lose a bunch of weight.
An ETI fuel cell, Shorai battery, TurnOne airbox and snorkel, and full Ti exhaust system can lose around 30 lbs alone.
BST wheels will lose several pounds more, but most importantly they will lose rotating and unsprung mass.
This will greatly improve handling and also suspension operation.
A lightweight rear brake rotor can save a pound or two.
Titanium is 40% lighter than steel, but I've found greater weight savings between steel and titanium for larger bolts than with smaller bolts, mostly due to the shapes of the bolts replaced.
You can substitute aluminum bolts in non-stressed areas as well.
The engine is the absolute heaviest component of the bike (next to the rider) at around 165 lbs.
There is nothing you can do to lose substantial weight on the engine.