Like most other abilities and powers in Blox Fruits, you can train Instinct (Observation Haki) by using it. But just enabling it won’t do that trick, and you must perform dodges. Each successful dodge will help you earn one mastery point. A great way to train Instinct (Observation Haki...
and change your range of vision. You will be able to spot enemies from further away and see their health and energy bars. At first, the observation Haki isn't very powerful, but as you train it, your range of vision will increase. ...