Make re-direct part of witness preparation
One of your primary goals in preparing a witness to testify is to get him over the nervousness that comes from testifying in court. You need to understand that your witness has watched television. He knows that the opposing attorney is just itching to have at him, to chew him up and spit him out. That's why mock cross-examination is essential, and part of that needs to be the reassurance that you will take care of any damage on re-direct. Convince your witness that you are going to be his "safety net". You will be asking questions that will clear up any misunderstandings. Done well, this allows the witness to relax, and makes him unafraid of answering the questions put to him on cross. And this adds to credibility. The jury will not see a meandering witness.
Prepare a strong question to close out re-direct
You must anticipate what the other side will try to accomplish on cross. That means you can formulate some rehabilitative questions when preparing for trial, and not merely on your legal pad during the questioning. At the very least, you should prepare a question or two that leaves your re-direct on a strong, upbeat note. If, for example, your witness is a doctor, you can be sure the other side will attempt to show bias. The traditional question about only testifying for plaintiffs might be asked. On re-direct, you could close with a question you asked during witness preparation: "Doctor, what is your primary purpose in testifying today?" The answer, of course, will be something like, "To explain the injuries as clearly as possible to the jury."
Do not merely re-hash the direct
Limit your re-direct to the most important issues that have to be dealt with. Don't go over every point made during cross. The jury will appreciate your focus, and the shorter re-direct gives the impression that there was less damage done than they may have thought. If you have more than one area to cover, make a quick assessment of the relative damage each area holds. Then, address these areas in ascending order. That is, start with the least damage and build, and cover the most crucial area last. There are two psychological reasons for this. First, most people assume that what is addressed first is most important. That's why dealing with something of relatively minor damage affords you an opportunity for a "quick hit". Second, the law of recency will leave the jury thinking about your rejoinder to the most damaging aspect of the cross, because that's what you'll finish with
If you forgot to ask a question on direct, ask the judge for permission
You don't want to be on the losing end of an objection for asking a question outside the scope of re-direct. If you did overlook a question on direct, approach the bench and get permission first. If the answer is no, you haven't lost anything in the eyes of the jury. It is the little things that, taken together, build a winning case. By spending some time considering re-direct examination for each witness, you will give yourself another small advantage, but one that might just give you large dividends