Cross examination is harder, because you're trying to argue with the witness, and they won't go along. You want to get them to drop enough things so that you can weave them together in closing argument. Prepping for cross-- have the evidence that supplies the answer to each question at your fingertips, so that you can whip them out if needed. Plan what objections there might be. A witness takes a credibility hit when they stand up at trial and contradict their own prior statements-- no point worrying about whether they contradict other peoples' statements.