TAKETHEHINT

Hints that should help you get on the right route and go for the right endings. Note: choices in the prologue don't actually matter--the ending is the same, regardless, though there may be minor variations in the scenes.

PROLOGUE

Pierre: Spend as much time with Pierre as you can. Then, when actually talking to him, make sure that you aren't too petty. Pierre likes talking about his interests, not his personal relationships!

Liam: Spend as much time with Liam as you can. Then, make sure you boost his self-confidence and don't let him compare himself to Pierre too much! He is optimistic, but everyone has self-doubt sometimes.

Ethan: Spend as much time with Ethan as you can. He doesn't hang around you as much in the prologue, so make sure that even around others, you show that you like Ethan as a person and believe in him.

POST-PROLOGUE (COMMON)

These are for the non-route common scenes.

When trying to get Liam, the first choice is the most important. Try to find the one where he is the only other character who appears until you get to the restaurant, as choosing this option unlocks a hidden one where you can get another point with him (or Laura--so this first choice is important for her, as well).
Staying behind and helping Laura won't automatically make her like you. Remember, Laura is very independent and strong-willed--the worst thing you can do is baby her or tell her she can't do something. However, keep in mind that if you do help Laura, you won't have time to meet with Angelina, who comes by afterward.
For the lunch scene, remember that Pierre will have less time for lunch... So he'll probably spend the most time with whomever he delivers lunch to last. Still, keep in mind the other person's personality when they ask you something or when Pierre decides to say something.
To get the normal/friendship ending, you need a tie in your common scene points. Randomly picking answers or trying to go for two characters at once should do it. (causing a tie between Ethan and either Liam or Angelina is probably easiest)

POST-PROLOGUE (ROUTES)

These are hints on how to get the romantic endings. The endings are all-or-nothing, so remember your choices. After getting a romantic ending, simply go back and change one of your choices and you'll be able to get the friendship ending.

Angelina: Try to encourage Angelina to live life the way she wants and boost her self-confidence. Also, she is a bit of a romantic at heart, so it's probably best not to be too cynical about things.
Liam: Push Josh to acknowledge his feelings for Liam and admit that he really does care about him. Also, Liam responds better when Josh threatens him/their relationship instead of just insulting him because he feels a more immediate sense of danger that way.
Laura: Be sure to never baby Laura or underestimate her--she hates that. Encourage her to pursue her goals without feeling the need to compare herself to others and always make sure she knows how important she is to Josh.
Ethan: Ethan finds it hard to open up because he's ultimately afraid of rejection. Show him that Josh values his opinion and worries about him, but do that without insulting him. Unlike Liam, Ethan responds very badly to harshness.