If a change hasn't been reviewed by another editor, a red exclamation mark ("!") appears next to the line for the edit.
If you have turned on "Enhanced recent changes" in your preferences then you can review all changes made to an article on that day at one go and mark them as patrolled.
There is an option to "Hide patrolled edits", which you can use to narrow it down to recent changes that still need attention. It is a good idea to turn it on and go through changes from the bottom of the list rather than from the top, so that there is less chance of bad edits slipping through.
Users who have been registered for longer than 30 days are marked as "autoconfirmed". In addition to this allowing them to review other edits, it also means that their own edits are patrolled automatically.
Therefore, there is no current way to use the patrolling feature to review edits made by users who have been registered for longer than 30 days.
See the [Mark as patrolled] link in the upper right, under the revision history number
In diff mode, you'll see a [Mark as patrolled] link for unpatrolled edits.
If the edit is constructive and substantially complies with Wikitravel policies, mark it as patrolled. Patrolling an edit does not mean that you have verified all the content of the edit as correct. Others familiar with the destination will check this using their watchlist and during subsequent edits.
However, when patrolling, in additional to blatant vandalism, you should also check for
Changing existing accommodation listings url or phone numbers to a consolidator, or agent.
Deletion of information, with no explanation in either the comment or the talk page.
Reordering of listings, without explanation.
If you are in doubt, don't mark the change patrolled. Someone else can double check it later.
Tools and techniques to help with patrolling
To be able to mark more than one edit at a time as patrolled, turn on "Enhanced recent changes" in your preferences. This will show recent changes grouped by article. You can then click on the "X changes" link to see all changes to the article and mark them all patrolled at once if appropriate.
If you don't see the [Mark as patrolled] link at the top right, it may be at the bottom right (always for patrolling newly created pages)
Start from the Special:Recentchanges, and hide bot edits, and patrolled edits. When you have the page looking how you like it, consider bookmarking it for easy access.
Open each of the diffs in a new tab (hold down the Control key in both firefox and Internet Explorer when clicking on the diff). and then use Control-TAB to review each edit in turn. Click to either undo, or mark it as patrolled, and cycle to next tab. When complete use Control-W repeatedly to quickly close all the tabs, or use the close other tabs menu item on the tab dropdown menu (Or if you are using firefox, consider the Close other tabs extension  for a keyboard shortcut).
If you have decided to revert a change, first mark it as patrolled, and then click the back button on your browser to go back and undo the change. This is much simpler than undoing the change first, and then marking the change as patrolled. Reverting a change does not automatically mark it as patrolled.
If you are using firefox, consider a extension that supports canned text, for easy revert explanations. Such as Paste Email Plus