Closing arguments should be more than a summation of the evidence.
For most of the trial the attorneys are limited to arguing the facts, what the evidence shows, and how it should be applied to the law. However in closing arguments the attorneys are given broad discretion to argue their case. Unfortunately attorneys fail to use this broad discretion, and only give a summation of the case in closing arguments.
Attorneys should try to develop a tool box of rhetorical devices they can use to argue their case in closing. Many of these rhetorical devices will be based on the three Means Of Persuasion. This includes using your closing argument to motivate jurors (pathos), analogizing the facts to other situations (logos), and discussing why they should believe your witnesses (ethos). Another rhetorical trick is people tend to favor information they can visualize. Many orators will analogize their arguments with a visual picture.
Jury instructions on weighing the evidence, including special jury instructions can be useful in closing arguments to attack certain pieces of evidence. Jurors will likely put more weight in statements from the court then the attorney. Courts routinely give instructions telling you to be careful of... evidence
CONCLUSIONS
Arguing the evidence and what the evidence proves should not be disregarded, but your closing should be more than this. An attorney can make gains in closing by arguing jury instructions, analogies, and other rhetorical devices.