Mass Effect 2's Suicide Mission is perhaps one of the most (if not the most) amazing final missions in any game ever, for so many reasons. The stakes are extremely high and failure is not an option - especially when considering the band of misfits you gathered to try and help save the galaxy.

It was essentially Bioware's own version of the DC universe's Suicide Squad. And if you make the wrong choices every single time, all of these characters (whom you've probably grown to care for), even Commander Shepard, will die.
Well, this guide aims to stop you from doing just that. In here, you will find the specific steps that will let you keep everyone alive during the entire mission, with a 100% guarantee. So without further ado, let's begin!
Step 1: Complete ALL Loyalty Missions
The loyalty missions for your squadmates are where you begin. Everyone you recruited will ask Shepard for help with personal problems. According to Tech Times, you can activate these missions by ensuring you talk to Yeoman Kelly Chambers and asking how the crew is doing. She will then point you to specific crew members who want to talk.

Approach the people who have their personal issues and say yes to their request. DO NOT DENY anyone the help they need. Here are the specific mission titles you'll see appear on your Journal after talking to enough people, including the DLC characters Kasumi and Zaeed (via IGN).
Jacob: The Gift of Greatness
Jack: Subject Zero
Miranda: The Prodigal
Mordin: Old Blood
Garrus: Eye For An Eye
Grunt: Rite Of Passage
Samara: The Ardat-Yakshi
Thane: Sins Of The Father
Tali: Treason
Legion: A House Divided
Zaeed: The Price Of Revenge
Kasumi: Stolen Memory
But be warned: FOUR loyalty missions out of all these can be failed. These are Tali's, Zaeed's, Thane's, and Samara's. Here are the conditions that will make you fail the four missions:
Tali: Present evidence of her father's treason during her trial
Thane: Lose track of the Turian politician you're tailing
Zaeed: Refuse to pursue Video
Samara: Bore Morinth or fail to attract her while in the club
Avoid doing these things during the missions and you will pass. But if you do fail them, every single one of these squadmates will die during the Suicide Mission.
Step 2: UPGRADE The Normandy
Now, it can be tough to upgrade the Normandy because you need to do some tedious resource gathering by scanning planets. But trust us that it will be all worth it in the end.

Three squadmates will give you the most important upgrade options for your ship, all of which will be available in-dialog during the break between the derelict Collector ship and getting the Reaper IFF, writes ScreenRant. Go and speak to these characters by choosing the Investigate option, to get the upgrades as follows:
Tali: Kinetic Barriers
Jacob: Upgraded Ship Armor
Garrus: Thanix Cannon
Assuming you have enough resources, you can purchase and install these upgrades at the Normandy's Research terminal.
Step 3: Give People The PERFECT Roles According To Their Skills
During Mass Effect 2's Suicide Mission proper, you will also be asked to assign roles to people. The main roles are as follows: fire team 1 leader, fire team 2 leader, maintaining the biotic bubble, and hacking the doors. But there's a final role: Normandy crew escort, which will help the surviving crew members (i.e. Dr. Chakwas and Kelly Chambers, if you managed to get there in time) return to the ship safely.

There are only a few people that would be PERFECT for each of the roles stated above. Here they are:
Fire team 1 and 2 leader: Garrus, Jacob, Miranda
Hacking the doors: Legion, Tali, Kasumi
Biotic bubble: Samara/Morinth, or Jack
Escort: Mordin
And that's it! These are what you need to do during Mass Effect 2's Suicide Mission to ensure that everyone, including Shepard, lives to fight another day.
Story posted on GameNGuide
Written by RJ Pierce