When writing your GRE issue essay, you'll not only need to give supporting evidence to help support your view, but you'll want to decisively make a stance, preferably at the end of the introductory paragraph. For example, consider that you are presented with the following issue topic:

People work more productively in teams than individually. Teamwork requires cooperation, which motivates people much more than individual competition does.

As with all of the issue essay topics, you can argue effective in favor or against the issue. It doesn't matter which stance you take, just as long as you make it clear which viewpoint you advocate. For example, if you are in agreement with the statement, you might include the following sentence somewhere in your introductory paragraph:

People work more productively in groups than they do when working individually because chores and duties can be appropriated to the most qualified individuals and cooperation can best leverage the skills of each group member.

In the above sentence, it is conclusively stated that people work better when in groups, and a bit of the argument is also included. Such a sentence is a great introduction to the remainder of the essay, in which you'd want to elaborate more on the reasons why working in a group is better than working individually.

Alternatively, you may disagree with the original issue statement, and so you might write in the introductory paragraph the following:

People are more productive when working individually. When work is performed in a group, responsibility is shifted from the individual to the group as a whole, and so group members often are lax with responsibilities, thinking that other group members will instead perform all of the required duties.

So, we've suggested that you provide evidence and that you take a stance -- two surely needed components of a well-organized essay. But, that's not enough. Why? Because not only do you need to do these things, but you also need to provide specific details to help support your view. We all have opinions, and so enumerating them is not enough. Instead, use specific facts and details to support your claim.

By specific details we mean real-world examples which support your view. For example, if you are writing an issue essay where you are arguing that children need to be fostered and encouraged to let their minds explore new ideas, you may cite Albert Einstein and his childhood fascination with daydreaming. Alternatively, if you are writing an essay arguing against the death penalty, you may want to cite indirectly the fact that several people have subsequently been found innocent of the crimes for which they were executed.