Before you follow this guide I would suggest that you finish the game or after you've seen some of the endings.

Continue
Blissful ignorance.


To get this ending you have to talk to Her about the book she is reading. She will give a quote out of the book that is necessary.
The story has to have progressed to the point where you know you are the brother and had the murder scene in the library.
After that go get the watch, look at it and wait. A similar scene will start. Two dialogue choices will pop-up. Behind you on the bookcase is the red book. Click on it and you'll repeat the quote. Just wait for the scene to play out. Don't click anything else.

Mindfulness
Present moment.


You have to stall the father for two minutes during the second library encounter. You can check the clock at the top. Has to centre on the 12. I waited about a minute before I selected the book so I repeat the quote. Then I waited again about 35 seconds before choosing the first dialogue option. Then I just waited it out and reached the 12.
After you get this achievement the option to continue the story disappears, so you have to reset your progress from the settings if you need more achievements or want to see a different ending.

Alone
All Alone.


Progress the story up to the point where where you witnessed the murder in the library.
Go get the watch, look at it and wait. The second library scene will start.
Select "Maybe it's better that we aren't together." and watch the scene play out.
This will take you to the alone loop.
You can go back to the library by taking the watch and setting the hand to 58.

Confessed
I'll do it.


Progress the story up to the point where where you witnessed the murder in the library.
In the new loop you can tell Her that you are her brother or you killed her father. That part doesn't matter. What matters is selecting the confession dialogues. Each time you can, say it's your fault and you'll come clean.
You need the watch in your inventory as well, so go get that before the Cop arrives.
Remeber to call Bumblebee so the Cop will talk. He will start talking with your wife as always, then she will say you have something to say. Confess to the Cop and give him the watch.

Coward
Not my problem.


This can be done before confronting the Cop or Her.
Just give Her the sleeping pills, make sure to turn the switch in the bedroom once, get the pocket watch, go to the closet, get the phone and wait. The Cop will arrive and shock himself. Cuff him and wait for him to wake up.
Once he wakes tell him you are innocent, and that you'll do anything to help him. He will get up and ask you for the watch. From this point on just do everything he asks and you'll get the achievement at the end of the loop.

Groundhog
The perfect day


To get this you have to know that the Cop only wants the Watch. Start off by calling Bumblebee and telling her about the watch. Then just play the scene like normal. Get ready for dessert, respond happy about the pregnancy and dance with Her. The Cop will arrive, but turn around after the call with his daughter. You will finish the dance and she will ask you what is strange. Just say that you really love her. She will go to the bedroom, you'll kiss and cuddle and get the achievement once the scene finishes.

Faun
The Poster


You have to look at the painting in the bedroom. There are 3 variants. The first one you get early on. I got the second one during the Groundhog ending. The third one becomes available after the first library encounter with the father.

Seasons
The Seasons


You have to look at the painting above the couch for each season.
The seasons change as you progress through the story. You don't have to look at them in one playthrough, just at all four in total. I viewed the winter painting (final one) first and then the other three on a later restart.

Ouroboros
The Egg


You have to look at the egg painting next to the radio. During most of the loops it will be a normal egg, then after you visit the library for the first time the painting will have a snake eye in the egg.
The final painting can be seen after the returning after the Alone ending. If you are in the Alone loop, just take the watch and set the hand to 58, then select to be with her. The painting will now be an Ouroboros.

Fluidity
Water the plant once.


Take a mug, fill it with water and go pour it on the plant in the bedroom.

Listen
Let it be.


I got this by accident. I left to go make coffee and got it. Once a loop starts just wait. Don't do anything. She will call you to the couch, you will talk and later she will kinda confess before leading you out the door. You get the achievement once she leads you out the door.

Gardener
Watch them bloom.


You need to water a plant with three flowers to get the achievement.
Keep watering the plant each loop to keep it from dying.
I got my first flower after the Coward ending. The second after the Groundhog ending and the third after the Confession ending.

Hope this guide helped a bit and you enjoyed the game.

Have a lovely day...