Specific tasks.
To get the glasses you have to talk to an old man where the dog is during Nimble Fingers and your perception has to be high enough.
Still trying to get the gloves myself, but I guess you have to get an A ranking in the fight.
The fedora you get by passing checks (I think) in Snooping Bonans.
For the pants after setting up the flag in the Delivery contract, you go back to the church and explore.
For the vest, you talk to the painter, ask about both people, go to the bar and talk to the guy, saying you're a DeLuca and buy the drink, then go to where the perception check tells you there is something to the east and look around there before going to the church and confessing your sins (which is a Cha check) then go to the graveyard and interact, before finally going back to the girl and confronting her. Then you head to the painter and finish it.