Dream Daddy

Generally speaking, your choices with Amanda don't really matter. However, there are a few scenarios which seem to count towards this trophy unlocking; I've listed them below.

Go for this trophy on a short playthrough where you're only dating Robert, as that's the quickest way to finish the game (takes about 20 minutes with text skipping). Every date you go on with Robert, provided you slept with him in the game's introduction (Bad Dad) will give you the option to just not go on the date (you'll either go to bed or tell Robert you can't see him anymore).

On the first day, after the neighborhood cookout, Amanda will go out with friends and come back late. The next morning, you will be in the kitchen with her – make sure you choose the dialogue choice “I trust you to make good decisions.”

Later in the game, Amanda will be crying in her room. Don't push her to tell you what's wrong, just leave her alone.

Other than that, just choose fun/non-strict dialogue. Basically, you're just trying to give her independence. This will unlock during the epilogue barbecue when speaking with Amanda (she'll give you a present).