Someone wrote up a blog post awhile back but essentially here are the tips:
1.) Don't get cocky or put yourself into a false sense of security, play like it's heroic difficulty.
2.) Confluxes: don't get marked, and everyone come down to the arena. if someone stays up top there's a higher chance for goblins to warp straight to the conflux. if you do get marked. run to the center and be careful coming back.
3.) As soon as the conflux(es) go away call it out and go to your safe spot. there's one on right side, 1 in the spirit bloom area, and one on top of the platform by the spirit bloom. be patient here and be careful of the green goo when leaving the safe spot
4.) call out minotaurs, use whatever to take them out.
5.) be careful with rockets. if you are a titan, look around and do a proximity check and call out when you are going to put down a bubble (blessings of Light)
6.) don't be afraid to run away, the objective is to stay alive. if you need help, call it out.
7.) stay calm, carry on, have fun
8.) oracles, call them out take them out quickly and take care of adds. make sure you can see at least 2 oracle spawns. and for the love of god don't stop moving.
9.) After oracles, take a breather, head down spirit bloom chest path. be careful you can still die, so don't pull a fig.
10.) gorgons. stick together guardians.there's 2 that you really have to watch out for, and make sure you heavy heavy and supers ready in case you need to kill 1 or 2 gorgons
11.) jumping puzzle. great time to take a piss break if you need it. Doing the spiral is the safest way across. go one at a time. be careful of the ledge. he is the true enemy.
12.) gatekeepers - 1 portal at a time 3 in the 1st to help out but 1 leaves before the gatekeeper is down. usually it's left portal first.
13.) after first team is back with the 1st relic, relic holder and assistant take 2nd portal, while someone goes mid.
14.) relic super and a couple IB or Gjallarhorn shots will take out the 2nd gatekeeper. 2nd relic must leave last. dont forget to cleanse.
15.) after 2nd relic is retrieved, everyone go mid. call out if you need help with praetorians.
16.) Atheon, aka glitch fest. Here's what to do when things eventually go bad
NO ONE TELEPORTED:
This is fine, kill supplicants and damage Atheon it is possible to kill him without times vengeance. just damage damage damage
1 PERSON TELEPORTED:
that person needs to grab the relic and get out ASAP. so the outside team better open up the portals. Call out the portals too. Jungle/Venus/Green/Right Desert/Mars/Orange/Left, if you don't get teleported but know where to look on radar call it out. anyways once relic is out make sure you cleanse and kill supplicants. Damage Atheon.
2 PEOPLE TELEPORTED:
Close but not quite. Safe strategy is to just hightail it out of there with the relic, but a 3rd person can go in and help. HUnters are best here if they have golden gun.
3 PEOPLE TELEPORTED:
Yay! now don't get sniped by the Hobs, or get beaten down by the minotaur. if you are jungle/green/venus/right/Future. grenade/rocket the minotaur/adds to help the relic holder.
If you are Desert/Orange/Mars/Left/Past use a suppression grenade or rockets that will one shot the hobs. or dont do anything and relic hold takes them all out. this side is easiest but can get really unlucky if the hobs all shoot the relic holder at the same time.
But if you come back alive you now have Times vengeance and can go kick Atheon in his Time bending balls to death. Gjallar back now,
For what it's like to run the hardest part of flawless, watch this video of my success:
Flawless Raid