What order of Marvel movies to watch before Infinity War

A quick google search reveals the following ORDER in which the MCU movies were released:

Phase I
1. Iron Man
2. The Incredible Hulk
3.Iron Man II
4. Thor
5. Captain America: The First Avenger
6. The Avengers

Phase II
7. Iron Man 3
8. Thor: The Dark World
9. Captain America: The Winter Soldier
10. Guardians of the Galaxy( GOTG)
11. Avengers : Age of Ultron
12. Ant-Man
13. Captain America: Civil War( Wikipedia includes it in Phase III, but i beg to differ)

Phase III
14. Doctor Strange
15. GOTG Vol.2
16. Spider-Man : Homecoming
17. Thor : Ragnarok
18. Black Panther
19. Avengers: Infinity War
20. Ant-Man and the Wasp
21. Captain Marvel
22.Avengers 4(Untitled)

Phase III culminates with Avengers 4.

To Understand Infinity War, you need to watch all the solo superhero movies(with the exception of The Incredible Hulk) and also those movies where the mad titan makes an appearance. But Most Importantly one must understand the story of the Infinity Stones too.

SPOILERS ALERT IF YOU DON’T WANT TO KNOW WHEN THE STONES APPEARS IN THE MCU!

Tesseract, or the Space Stone, first appears in Captain America: The First Avenger and then In Avengers 1.
Aether, or the Reality Stone, appears in Thor: The Dark World.
The Eye of Agamotto, or the Time Stone, appears in Doctor Strange.
Orb, or the Power Stone, appears in GOTG(2014).
Scepter,or the Mind Stone, appears in Avengers 1 and Avengers: Age of Ultron.

Now, to understand what is going on in Infinity War, you can either watch all the movies(To get a stronger grasp on the way of working of each metahuman) or you can watch it this way:

1. Iron Man
2. Thor
3. Captain America: The First Avenger
4. The Avengers
5. Thor: The Dark World
6. Captain America: The Winter Soldier
7. Guardians of the Galaxy( GOTG)
8. Avengers : Age of Ultron
9. Ant-Man
10. Captain America: Civil War
11. Doctor Strange
12. GOTG Vol.2
13. Spider-Man : Homecoming
14. Thor : Ragnarok
15. Black Panther

The reasons i have not included Iron Man II and III and The incredible Hulk is because they focus on individuals and don’t really add up to the bigger plot. Although Iron Man II introduces Natasha Romanoff(Scarlett Johansson), an important character. So it’s up to you to decide which one to skip and which one to watch.