The first four seasons are very close to the first 3 books, with a few exceptions.The fifth and sixth seasons have cut/changed/rearranged a lot of elements, so some plot point match and others you'd need to read up on. Here is where the main characters are by the end of the last book:

[Spoilers Published[(/s " Similar to/Beyond the books

1. Bran: Still with 3ER. Jojen is alive.

2. Cersei: Just finished walk of shame.

3. Jaime: Never went to Dorne. No Bronn.

4, Jon: Still dead in the books.

1. Arya: Still training as faceless man.

Different from Books:

1. Sansa: Still in the Vale with Littlefinger. Never married Ramsey.

2. Brienne: Still looking for Sansa. Met with the religious group who helped the Hound. Captured by Brotherhood without Banners.

3. Tyrion & Jorah: In Meereen, but not with Danaerys.

4. Stannis: Still alive. Hasn't fought Ramsey yet.

5. Davos: Sent away by Stannis to recruit Northern lords.

6. Samwell: In Oldtown, training to be a Maester. Never returned to his parents.

7. Theon & Asha: Never went to Meereen. Both held by Stannis.

Minor Differences

1. Robb's marriage was more complicated, likely planned by Tywin.

2. Stannis left Melissandre, his family, and a number of his men at the Wall.

3. Loras is a Kingsguard and has two older brothers.

4. Cersei is much more paranoid and self destructive.

5. Jaime and Cersei have had a major falling out, and Jaime is becoming a much nobler character.

6. The Brotherhood without Banners has a different leader.

7. Jorah doesn't have greyscale.

Major Differences

1. Varys doesn't really support Dany; He supports a boy he claims is Raegar's son "Aegon". Aegon travels with Tyrion for a while, and has launched his own invasion of Westeros.

2. The Ironborn are way more important. The Kingsmoot is much more impressive, and Euron wins after showing off a horn that can supposedly tame dragons. Theon's other uncle "Victarion" is the one travelling to meet Dany.

3. The Dorne story is completely different. Doran is secretly working towards revenge, with the help of the Sand Snakes. He has two other children, Arianna and Quentyn, who are POV characters.

4. A lot of people dead in the show are alive in the books.")