First time writing one of these, but I'll try to explain them.

1. Anything with Haley...

So in my play through of Season 1 & 2 I basically didn't do anything for her so when it came time for season 3, I didn't get many achievements. So I had to go back and play 1 & 2 again. After that, the achievements were easy.

2. Lillian's Back Door...

To get this one you have to:
1) Refuse all advances from Cassie
2) Say you have a crush on her (Lillian)
3) Play through the whole story again because you don't get the Cassie route in the end

Every other achievement is SUPER easy, just pick different choices for each.