Harbinger

The first opportunity for influence can be found when first entering the Harbinger. There will be a tutorial about influence, then say something nice to Atton or Kreia to gain influence with either. I recommend Siding with Atton here.

- "Atton's Plan was a good one - Let's head to the bridge and get the drift charts." - Atton Influence
-"Forgive me, Kreia, I was distracted for a moment. I'll be more mindful of the Present" -Kreia Influence
"Watch that tone, old woman - I will not be lectured by you." - Negative Kreia Influence


Harbinger Lower Floor

Atton will introduce his meta-mechanic of warning you when you should save your game. Say, "We'll have to be careful, then. But we have to keep moving"

Fuel Depot

When you find T3-M4 in the fuel line, compliment him to gain some influence

Exchange base (Dark Side)

Ensure Kreia is not in the party for this part, as she disproves of needless violence.

Threaten and kill the doorman for Atton influence. You can leave the area, come back, and repeat this two times for additional dark side alignment, but not additional Atton influence.

Inside, threaten/Kill the receptionist and gain Atton Influence. (Dark Side)

You can add Kreia to the party once again after these options have been selected.


Hidden Jedi Base - Telos Polar Region

Handmaidens
Before freeing your party from their force cages, talk to one of the Handmaidens about Atton's Echani training.

Atton
Talk to Atton about what you discussed with the handmaidens. Talk to him again and tell him that you think his Echani training could be an asset for Atton Influence. Avoid the Persuade option unless you want negative influence.

Bao-Dur
Tell him the crash wasn't his fault

T3-M4 (Needs to be verified)
(Light Side) Compliment/Reassure him after you free him.

You can gain a great deal of influence after telos while on the ship, but I need to replay the game to record everything. For now, this is a placeholder.

I like to do Nar Shadaa next as you unlock three companions on this planet and I don't have to worry about missing influence opportunities with NPCs on other planets.

Mira or Hanharr
You may want to ensure that you are either Light Side if you want Mira, or Dark Side if you want Hanharr. Upon reaching the docks, the game decides which companion you get. After the cutscene plays that introduces them, you are locked in, and you can then gain the opposite alignment if that is your preference.


Main Area

Man Getting bullied near the landing pad
(Light Side) Start with Visas and Bao-Dur in your party. Help the man getting bullied.

Charity or Cruelty scene
Pick your preferred alignment option. When she gives you her lesson, tell her you will think about it.

Droid merchant
(Light side) Have T3-M4 in your party, Sympathize with the droid and free him.
(High Intelligence) Dismiss T3 and with Visas in your party, and after you returned the droid, extort plans from TT-32. Visas likes your manipulation.

Man by the pit getting bullied by thugs
(Light Side) Have Bao-Dur and either Atton or Handmaiden in your party. Help the man and demand nothing in return.
(Dark Side) Have Atton in your party. Force persuade them to jump in the pit for Atton Influence


Refugee Sector

Sick Man
(Dark Side - Needs to be verified) - Have Kreia in your party, talk to him, and then tell the leader of the exchange in the area that this man needs to die to prevent the disease from spreading
(Dark Side) - Have Kreia and Visas in your party. Convince him to kill himself.
(Light Side) - Have Bao-Dur and Handmaiden or Atton in your party. Avoid having Kreia in your party. heal him with your treat injury skill.

Hussef
(Dark Side)(Needs to be verified) - Have Kreia in your party. Convince Hussef to submit to the exchange through actions in the refugee sector that discourage the refuges.

Speeder
Bao-Dur, Atton, T3-M4. Save your game before interacting with the speeder because I don't remember 100%. If I remember correctly, you can gain influence with all three of them by getting them to check your work after various steps. Otherwise, I recommend prioritising Bao-dur here if you don't already have enough influence for him to become a jedi.

Atton Backstory
Take Atton with you to talk to the Twi'Lek that knows Atton. This is required to make him a Jedi.


Docks
(You may wish to finish all other business before coming here)

Flophouse, Lootra
(Dark Side) With Kreia in the party and no one else, Lie to Lootra that his wife is dead.
(Light Side) Kreia and Atton, Bao-Dur, Disciple, or Handmaiden. Talk to lootra, go to the refugee sector and rescue his wife. Return to Lootra. Kreia scolds you (softly) but doesn't reduce her influence. Tell her that if it meant your life, there is nothing I would not do for you or any of my allies. The other party member likes this.

Mandalorians
You can come back to this planet later, once you have Mandalore in your party, to send them back to Dxun

Docks

Protocol Droid
With T3-M4 in your party, talk to the protocol droid.


Khoonda Exterior

Mechanic
(Awareness) - With Atton and Kreia in your party, ask him why he is so busy. Persuade him to get more info out of him.

Droid Merchant
Have T3-M4, Mira, or Bao-Dur in your party. Show compassion to the droid merchant. (This may also work with HK-47 or G0-T0, but this needs to be verified).


Crystal Cave
Before Entering the Crystal Cave, take the Atmospheric Sensors quest. Saedhe, just across from the cave, offers it.

(Repair or Awareness) - With Bao-Dur in the party, interact with the rubble at the base of the pillar near the entrance.

Mercenaries
(Dark Side) - With Visas in your party, tell them that Vrook belongs in his cave
With Kreia in your party, tell them to ship Vrook to Nar Shdaa

Mercenaries (Outside the Cave)
(Dark Side) - With HK-47 in your party, tell them "Die, mercenary Scum!"
With Handmaiden in your party, hear the mercenaries out.


Enclave Sub Level

Jorran
(Dark Side) - With Kreia in your party, tell Jorran that the Laigreks are dead when they are not.


Mandalorians
You can come back to this planet later, once you have Mandalore in your party, to send them back to Dxun. They are down the path from the salvagers (In the direction away from the Jedi Enclave ruins. but on the same map).

Wilds - Bounty Hunters
With Mira in your party, tell them that Mira is a real bounty hunter.

Jungle

Lost Mandalorian
(Dark Side) - With HK-47 and Hanharr in your party, kill him
(Light Side) - With Disciple and Bao-dur in your party, Help him down and promise not to turn him in. With Handmaiden in the party, say "The war is long over"

Docking Area

Guard
With Kreia in your party, Force Persuade the guard to let you into the city, and then tell Kreia that she has a valid point.
With HK-47 in the party, Force Persuade the guard to let you into the city, and then say "never stop me again"


Merchant District

Anda
(Siding With Vaklu / Dark Side) - With Visas and Mira in the party, agree to remove the guard captains and tell her that the credits are hard to ignore.
With Kreia in the party, "I want to see where this leads."

Terlyn
(Light Side) - With Visas in the party say, "The darkness clouds your mind's eye, Visas. Compassion can create problems, but it is a source of greater strength."

Angry Crowd
Call for an end to the monarchy for Mandalore influence. Tell him that we need to help Vaklu if we want his support. (It is unclear if you say this now or during the riot).
With Hanharr in the party, support vaklu (Needs verification)

Politics Aliens
With Visas in the party, side with Vaklu


Cantina Exterior

Bounty Hunter
With Mira in the party, a bounty hunter attacks you. Stick up for Mira, and refuse to let him harm 'your friend'.

Droid Merchant
With G0-T0 in the party, tell the droid to reset his prices.


Starport Visa
This covers several areas of Onderon, but as you only get two, I figured I would group them up together.

Xaart, Republic Spy in the cantina
With Handmaiden, Bao-Dur, Disciple, or G0-T0 in the party, give him one of the open starport visas.

Terlyn, parent with kids in the merchant district
(Light side) - With Handmaiden, Disciple or G0-T0 in your party, give Terlyn an open starport visa.

Sakarie, black market trader in the cantina
(Dark Side) - With Hanharr in your party, give her an open starport visa.


Jedi meeting and the aftermath
Choose your party member before the meeting with the Jedi for influence during this scene.

Jedi Meeting
(Dark Side) - Visas needs to be in the party before the meeting with the Jedi. and after Tobin's soldiers attack, agree to cleanse the bar of life. Forbid it (Light Side) to lose influence.
(Dark Side) - HK-47 or Hanharr needs to be in the party before the meeting with the Jedi. Say "Kill them all".
(Light Side) - Handmaiden needs to be in the party before the meeting with the Jedi. Agree not to harm anyone.

Riot in Merchant district
With Mira in the party, stand around and watch NPCS kill each other
HK-47 Relishes the carnage, but it's unclear if you get influence from this interaction. (Need to verify)
With Hanharr in the party, support Vaklu
(Dominate Mind) - With G0-T0 or Disciple in the party, force persuade him to stop the riot.

Palace

Queen Talia Alliance
With Kreia in the party, tell Talia to kill Vaklu, or let her decide.
With Mandalore in the party, tell Talia to kill Vaklu

Valley of Tombs

Bodies
(Negative Influence) After Kreia warns you to leave the dead alone, you gain negative influence if you ignore her advice and loot the bodies.

Tomb of Ajunta Pall
(Awareness) (If you selected the lore options for Revan to be light side) - Listen to the story, then select, "No one is beyond redemption".

Telos
(Dark Side) - With HK-47 in the party, provoke the wounded soldier instead of healing him.

The Ravager
With Mandalore in the party, kill Tobin

My primary source for this guide was Gamespot: Star Wars: Knights of the Old Republic II - The Sith Lords – Influence Guide. This guide is wonderful, but I wanted a linear, more user-friendly version of the guide.

Youtube: Atton Influence Opportunities (LS) by tehPrincessJ

If you tell me an influence option that I missed, I will credit you here: