What strategies are most effective for Symmetra turret placement?

Symmetra is an interesting builder character in Overwatch. Rather than one beefy turret like Torbjorn, she places many smaller turrets (up to 6 at once!). The turrets are very weak, though - one hit will kill them. To effectively use these turrets, you have to satisfy two criteria:

1) They need to have close ranged line of sight on enemy players

2) They need to be in an area that enemies are not expecting, nor can they easily shoot at

On paper, I understand that pretty well. However, I'm having a lot of difficulty putting this into practice as I'm getting matched up with more and more savvy players. I'm not asking for a list of areas to place my turrets. I'm asking for general strategies on how to identify an effective place for turrets.

Solution 1:

Turrets: these seem pretty strait forward but can actually be used in a variety of ways. Obviously the most strait forward is to cover choke points. This is extremely effective IF you can place them in such a way, that is inconvenient for the enemy to have to destroy. For example, if you place turrets above the enemy, on to your side of the wall, when they walk through they are forced to look up to shoot it. They are using that time to look up to shoot the turret and not your team. That's a minor victory in my book. How I like to use the turrets however is a bit different, and I'll tell you why. Symmetra gets notifications when her turrets are attacking, or when they get destroyed. I generally place 3 at the choke point if I'm defending, and I'll place the remaining three around the area where sneak attacks are common. This allows me to spot the attack well ahead of time and warn my team mates. Do not under estimate this, it's extremely useful. Also they slow, so there is that. I should also note that the turrets can be placed ON payloads, so when attacking you get mobile turrets, which can be nice. (I don't cover turret placement itself very well here, that's a topic in and of itself. however there are good tips from other commenters below)

Source: https://www.reddit.com/r/OverwatchUniversity/comments/4lmr4u/why_symmetra_is_amazing_and_how_to_use_her_kit/

Don't hesitate to read the Reddit post, you have many more information about the rest of Symmetra's kit and the synergy between her abilities !

Solution 2:

I place turrets around door frames or on walls/obstacles that enemies are likely to run past. For example, the payload maps have flanking routes that connect to the main path via a doorway or narrow passage. Drop your turrets to surround it so that someone trying to flank will get zapped the moment they set foot through the door. A (not good) example would be the mining tunnel at the start of Route 66. Doorways are good because the majority of heroes will have to step into them in order to clear the turrets. Another decent spot would be the KotH maps that have ceilings on the control points, such as first stage of Illios or second stage Nepal. You want the LoS to your turrets to be as short as possible.

Watch the routes the enemy is taking and place turrets in the blind spots on those routes. As you play the maps more, you'll figure out the most popular routes and that will in turn help you figure out where to drop turrets. Symmetra isn't the best for getting up in the thick of the fight, but she is really good at protecting flanks.