Warding is one of the things in Dota 2 that takes a while to get a feel for. Where you should be warding will change depending on the situation in the game you're playing, the same goes for when you should be warding. The three most common types of warding are: Defensive WardingOffensive WardingRiver WardingDefensive warding is primarily focused on giving you and your allies vision on your side of the map. You usually ward defensively when you're playing up against heavily gank-oriented lineups or if you're playing with extremely farm-dependent cores (Hyper carries such as Spectre for example). Common ward spots for defensive wards are at the entrances to your team's Jungle and your team's ancient creeps. Defensive warding is also usually the thing you do if you're behind and wish to take engagements near your own towers and your own highground, for maximum efficiency. Offensive warding is the exact opposite. It focuses on giving you and your allies vision on the enemy side of the map, so you can get easy pick-offs on enemy cores either in lane or in jungle. Offensive warding is usually done when you're playing a heavily gank-oriented lineup, which relies on getting kills to snowball or if the enemy team has a heavy farming hyper carry that needs to be shut down. Offensive warding is also good for sniping couriers and in general getting intel on how the enemy team are progressing in terms of items. Usually offensive wards are placed in the enemy jungle, near the enemy ancient creeps, in between towers in enemy lanes or in the enemy base... Outside of tower range of course. River warding is what the name implies, wards that overlook the river. They fall into a mixture of both defensive and offensive wards, as the river is the middle-ground of the map. River wards are probably the most commonly placed wards in the entire game as they are used to keep tabs on rune spawns, jungle entrances, river ganks and Roshan. It is very standard at all skill levels of Dota, to place one of your two starting wards as a river ward. Arguably, River wards are the most "value for money" wards, as a single ward can give you information on runes, Roshan and incoming ganks through the river, That being said, they're also the ward type most susceptible to being dewarded, so be ready to defend them if it comes to that. There are also some less common warding types such as Lane wards or Camp wards. Lane wards are used to give your cores a helping hand by granting them vision over their entire lane, making incoming teleports to the enemy tower and enemy support rotations easy to see. Camp wards are used to block enemy jungle/ancient creep camps. Strong if you want to mess with the enemy jungler's progression or if you want to prevent the enemy supports from pulling, but mainly relevant to offlane core players. As for when you should be warding: Usually when there's a spot of downtime in your game. If a big teamfight has occurred or if your team is invading the enemy jungle, grab some wards and plant them while you're safe around your allies. Ideally, you always want to have wards active on the map.