How Do I Find Page or Post IDs?
Wordpress doesn't make it very easy to find IDs for pages, posts, categories, or tags, but there are two ways to find them.
Manually Locate IDs
You can hover over the "Edit" link in your page or post list and notice the web address variable. It will be "domain.com/wp-admin/post.php?post=50" where the number 50 will be the ID.
Use a Plugin
When we use X-Ray Serp ourselves we install a free plugin called Show Post & Page IDs (download here), which adds an ID column in the listing table for pages, posts, tags, and categories.
Is There An Easier Way Than Using IDs?
Unfortunately, no. The alternative would be using page or post titles, but that takes away the ability to specify a wide range of IDs at a time.