I have always been a big fan of using plain text editor for XML files rather than GUI based XML tools. But working with plain text editor can be cumbersome. To be able to work with XML files, editor should be able to display XML files in proper format with line breaks, validate if a tag is missing, validate against a schema and so on. I generally use notepad++ for this purpose.
This post will help to install XML tools in notepad++. You can get the notepad ++ from here, if you don't have it now. Follow below steps to install XML tools: