Dota 2 Vision, Wards, and Smoke
Observer Wards on cooldown, sentries for deward, smoke for a kill that becomes a tower.
Observers
Buy them when they are in stock. Place them on high ground that sees a rune, a camp, or a gank path — not in the lane you already have vision of. A ward that sees a smoke is worth more than a fourth damage item on a four-position.
Sentries and deward
If your wards die instantly, they have sentries. Deward the obvious cliffs before you smoke. Detection for invis heroes is a team item: sentries, dust, gem later. Guessing is how you feed the same Riki for 30 minutes.
Smoke
Click it in a safe spot, walk fog, hit one target, take an objective. A smoke that breaks on a ward is an execute you skipped the deward for. Announce it. Do not smoke as two people while three farm.
Watchers and outposts
Click watchers on a rotate. Capture outposts after fights. These are free vision and XP that pubs skip for one more jungle camp.
Where not to ward
The same cliff every game. The river floor that expires when a power rune spawns. Inside your own T2 when you are winning — that ward should be in their jungle.