You want to paint, but the canvas is blank. You want to write, but the page is empty. No matter how you frame the photo, the shadow from the cypress tree doesn't set the right mood. When you play back the recording, the song is just ... off. You want to create something, but you're just not getting it right.
The exact same thing is what makes copyright law so complicated. Copyright law combines legal analysis and creative expression. Part of the copyright cost, especially in litigation, is amassing evidence that one song sounds sufficiently like another or a computer program used elements of an existing one. Copyright litigation requires photography critics and experts on programming languages to mull over the works, count the differences, and weigh their significance.
These experts look past the choice of color, the poem's alliteration, or the code's annotation. Copyright law requires analysis of creative works in the abstract. Copyright protection extends beyond simply duplicating the original work. Minor or cosmetic changes or minimal modifications are not always enough to avoid infringement. There has to be something to the work that gives it its own creative expression.
The first step of how to copyright something is to know what the "something" is. Getting to the something is what makes it difficult to describe how to copyright a name or how to copyright an idea. A name is just a name. An idea is just a start. To copyright something, you've got to create something.
That special something
The"something" doesn't come easy. It is the creative spark that makes the photograph haunting, the story compelling, or the painting gorgeous. The more creative and compelling your something is, the more valuable your copyright. Your generic detective story, your stock moody black and white photograph, or your work that is barely different from so many others is not going to garner copyright protection.
When you've created something, make sure you understand it in relation to other, similar works. Know why you framed the photo to get the cypress shadow just right. Know why you selected the characters you chose and made them part of the story. Be able to understand how those works are unique and then look for them in other works. Copyright infringement is easy to detect when someone reprints your photograph or sells bootleg copies of your song. Much of copyright infringement, however, is more subtle.
Determining what infringement is
Taking something out of your work, and making something new can still constitute infringement. If it's a minor part of your work—a part of the background in your drawing or a description of a setting in your story—its use is less likely to be infringement.
If someone takes the something that makes your work special, then that is infringement.
Which is what makes copyright law so difficult. In the end, copyright has to apply legal rules to human creation. It has to measure one work against another and see if it's too similar or legally different.
The one way to make your copyrights simpler, and easier to enforce, is to know the "something" that makes each work unique in the first place.