This is a carbon copy of http://www.leagueoflegends.com/board...d.php?t=237436 and I will update accordingly here
As most of you know wards are an important part of map control which leads to winning games.
I've noticed myself though that while some players do place wards, they do not place them in good locations.
I'm not a high elo player myself but I have come to a degree of understanding of wards being a former DoTA player myself. And so I have here a simple guide to placing vision wards. (If you're high elo you probably know this already)
AFAIK Sight wards are used to
-Ensure important objectives are locked down (Buffs, Dragon, Baron, jungle as a whole)
-Increase overall map control (placement in choke points)
-You can usually use sight wards as a target for friendly units as well, this means you can teleport to them, and certain spells such as Jax's Leap and Katarinas Shunpo can be cast on them to close gaps or escape.
-Wards can be placed without breaking stealth (twitch, eve, shaco to an extent)
-Try to keep wards in a bush if possible, this means an enemy with oracles will have to be in the bush itself to see/kill it. Also a bonus of vision in bush as usual.
-Wards can be displaced using knockup abilities, e.g Alistar and Chogath (baron if you place it near enough) and this is highly annoying since it was probably placed beautifully (like in this guide), and those mofos just ruined it.
-Wards die in 3 hits no matter what your AD is.
With this in mind, the ward is an item that lasts for a limited time, and therefore its maximum potential should always be used. Any less is a waste of gold on the ward placers part.
Placement of wards besides main objectives are usually dependant on the time of game, what your team/enemy team is doing.
e.g you want to push, you might want to ward river (1st turret) enemy jungle (2nd turret onwards) or even both to watch out for approaching teamfights/ganks from jungle and respond accordingly
OR you want to defend, you might want to ward river/your own jungle for similar reasons
One thing you may want to add is how ward priorities shift over time. For example your team is getting beat back, you no longer want to ward middle etc as you are mostly fighting out of your base. Important places to ward at that point are the jungle in between your lanes, specifically your red/blue buffs as your teammates will want to go into jungle to switch lanes or grab buff and get romped by other team.
Obviously you still want to try to ward baron if you can but realistically you have no chance of stopping a good team from getting baron late game when playing defensively. Especially when an inhibs down as they can see you fighting the monsters.
Conversely when you are hitting their base hard you want to start forgetting about warding things on your side and ward their jungle more. Catch their guys trying to sneak around behind you etc.
Basic rule of ward placement - if you leave the fountain with free item slots, more than 90 gold and no wards, you are doing it wrong.
-oracles elixer. This of course means you will need to actively seek out wards to make it worth your while, however knowing when a ward is nearby is a great advantage, it means you know that the enemy knows you are in that particular location, meaning you are that much less likely to get taken by surprise/ambushed. Killing a ward also frustrates enemies (especially the one who placed the ward) Facechecking bushes is another matter entirely.
-counterwarding. This means either taking preemptive measures to watch out for the enemy, or using vision wards (the purple wards that detect stealth) How does this work? When you suspect the enemy has a ward on an objective you want to meet such as killing the Dragon you either ward a chokepoint nearby where the enemy must pass through to get to you so you can escape before they arrive or countergank them, OR placing a vision ward in that very location. Vision wards allow you to see and kill nearby wards and stealthed characters, and has vision over the area for a short time too.
-Spells. While spells no longer directly reveal wards, there are still spells that pseudo detect them. Evelynns hatespike, and Sorakas starcall will toggle and allow you to cast it even when there are no nearby enemies, telling you there is something stealthed nearby. For champs like Kat and Morg their ults can also be used to detect stealthed champs, they'll helpfully be castable when no champs are nearby telling you theres a sneaky rat (or seductress) around.
For all those asking for the champion portraits, you can find out how to change them here.
I have attached examples with details below, I'd appreciate any feedback on the topic myself so I can fix anything that's wrong with this.
Mouse over the thumbnails for relevant image names (generic ward placements will sound generic e.g crossroads 4)
Summoners Rift pics are generally greener, while Twisted treeline is a darker blue.
I reccomend browsing all the images to get a grasp on my color coding and notes etc.
Twisted Treeline (photobucket)
Summoners Rift (photobucket)
Note: these cover locations with 3+ roads, 2 way warding locations are no brainers