Aside from the normal dialog choices there are instances where you have an option to chat with certain characters. This will bring up 6 topics to talk about with 3 choices per topic for a total of 18 choices. There are 3 possible reactions to the choices: bad, good or excellent.
You want to try and get 100% good reactions because having either all bad or all excellent often forces the chat to end and you won't receive some items that are needed. If it's impossible to get 100% good reactions try to get most of them good and then one excellent, just no bad ones.
How to distinguish the reactions: Bad always results in the character frowning or being clearly displeased with a dark blue background. Good reactions have a bright blue background and the character reacts well to the choice. Excellent reactions have a bright pink background with the character having varous reactions from happy to embarrassed.
You can press triangle and go back a choice if you get a bad reaction and try again.
There are numerous moments where Ryuuji is able to clean around. It is advised that you always choose to clean whenever you are prompted to. There is no penalty for cleaning so you don't have to be concerned. You will always have less cleaning kits than available cleaning spots so be careful in your choices. There is almost always an important item around that'll unlock a choice, one or more junk items that are not useful for anything and one or more spots with no item. Make sure you quick save before cleaning so that if you get it wrong you can just reload.
Moving around the town
Aside from the more complex dialogs and the cleaning mechanics there are also several moments when you can move Ryuuji around town and meet up with certain characters. This feature is not hard to use but be warned that certain events only last for a while or won't even be triggered depending on the order of the characters you talk to so be careful who you choose to talk with. I will only list down the characters you need to talk to, all the others I do not list but are there are either unnecessary to talk to or will trigger the wrong scenes. You can try and mess around but make sure you save before you do.