Well it was not exactly a success, but did anyone expect something else?
Trump boasting about what good friends he and Kim are, really
Kim is not the easiest character to talk with, and when you can achieve a cheap "victory" by humiliating the world's leading nation you probably use the incident. If this is especially clever.. i don't think so.
Kim is of course backed and partially controlled by China. Usually there are negotiations between nations before the leaders meet, so the agreements are prinicipally done beforehand, and they only mee to sign the negotiated contracts and show the world how great they are. Trump obviously has no clue about negotiating, and he did not do his homework.
Question is if the outcome could have been any different with better preparation.