One way I stay alive is avoiding these problems all together.
Random grenades come from players, correct? Where would a player throw such a grenade? In the direction he believes enemies are in.
Question is, how does your position get revealed to your enemies? It's one of three things:-Your teammates. They can either be firing unsilenced rounds or can be just walking around uncloaked near you.
-The enemy sees your position on the killcam after you kill him, or he just throws a grenade to the position he died in to get lucky.
-You're not moving very strategically and your position is being revealed as a result. This includes sprinting head-on at groups of enemies and moving across open ground without scanning the battleground beforehand.
To avoid these problems:-Keep a distance between you and any noobs on your team. Don't pay the price for their reckless mistakes.
-Relocate yourself after every kill, so that your enemy's luck grenade won't hit you, and the enemy team won't be able to simply find you near the location of the kill. This would also help in surviving backshooters.
-Scan open-ground areas before you decide to move through it. It's essential to have at least some knowledge of your enemies' whereabouts before moving in for a kill. This includes enemies watching your target, possible camping noobs in the area, and snipers.
Being killed by a backshooter is usually caused by either you being reckless or your killer being stealthy or tactical.-You're firing at a target while you're on open ground, easily spotted by any nearby enemies.
-You decide to attack a target without knowing if he's alone or with a teammate.
-You play carelessly, not turning around to check your six every now and then.
-You charge at a hologram like a savage beast.
To avoid these situations:-Always fire from a safe/partially safe location. Either be behind cover or near some easily-accessible cover. Don't leave yourself open.
-Use your Visor to find enemies instead of just running and leaving it all to chance whether you missed an enemy or not. This is by far the most useful advice I can give you for survival and tactical play.
-Turn around often to check your back. Everybody is very familiar with the common backshooters and backpunchers that cloak and get behind you for easy kills.
-Don't just sprint at any target you see; take a second(literally a second) to anolyse his movements. Is he out of energy? Is he moving towards me because I'm tagged? Does he feel secure enough to walk across the field unguarded? IS HE REAL? For the hologram case, the visor also provides you with invaluable information. You won't be able to tag a hologram.
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That's about it when it comes to survival and tactical play for me. I try to practice these as much as I can while playing. To play strategically, you won't be able to just sprint around looking for prey like a wild animal(you get used to this after scoring high a good number of times), so your number of kills may go down a bit until you learn to use your gathered information to your advantage.
Also don't expect these things to completely stop happening. Unless you're so good that you'll never get caught from behind, you're bound to get shot in the back every once in a while, I know I do! Random grenades... it's hard to avoid them when they always fly directly towards you, isn't it?