Bit of background....I have been doing MTurk for about 4 weeks. Yesterday I went over 1000 hits. Rejections have come my way as a part of doing business. My approval rating is, at the moment 99.71%. The two things I try to do is first look at the requester reject rating via Turkerview. If the requester is red and has rejected then I stay away. If rejections do show up I make certain to, politely, question the rejection based on their reasoning. I ask for the rejection to be reversed and redo the hit if possible. Had I not done this I would be sitting at 52 rejections now instead of 3.