What qualities did valdak display in MAUS that contributed to his survival

There are a number of reasons. Certainly luck has something to do with it. Beyond luck, Vladek was extremely resourceful. He was able t adapt to different situations and jobs making himself useful to the Nazis. Vladek was great at saving things, which Artie can't stand after the war, and using what little he had in the best way possible. Vladek was even able to help Anja countless times. Really she brought out the best in Vladek who in turn strived to save her as well.