Warding in DotA/DotA 2 is an art. Those who know how to utilize observer and sentry wards better will have a significant advantage. This article is to help you learn more about the art of wards.
Ward basics
Wards come in two types - observer and sentry. Observer wards grant vision of an area of sight for 6 minutes at 1600 range at both day and night. Meanwhile, sentry wards grant true sight (reveals invisible units) for 3 minutes at 950 true sight range and 70 normal sight range.
Observer Ward
Sentry Ward
Legend
Red - Rune wards
Yellow - Ubercliffs
Pink - Lane/aggressive/defensive/ wards
Green -Jungle wards
Blue - Push wards
White - Very situational
Purple lines - Blocks the pointed neutral camp from spawning
I will cover each spot in the order listed in the legend. In each section, they will be covered in top-to-bottom order on the minimap, and left-to-right if they are relatively the same height. (The only section that will disobey this rule is the push wards section.)
Each spot will have two screenshots accompanying it, with the 1st screenshot having a red circle to highlight the ward position.