Ward for your next objective
Vision is most useful when your team can act on it. Decide what you want to protect or contest before placing a ward.
Protect the approach
When your carry farms a dangerous lane, vision on likely enemy approaches can buy time to retreat.
Prepare before a fight
Arrive with teammates and place vision before contesting an objective. Walking alone into darkness to ward can give away both your life and your plan.
Practice
For each ward you place, name its purpose: protect farming, scout movement, or support an objective.