You can create subdocuments by inserting other files into your master document.
By default, Word save all documents in the newest format (*.docx), but you can change the default format to doc or anything else.
You can use superimposing characters for easy and fast entering text without using Equation.
By default, Word shows document tooltips when you hover on a button, but this option can be turned off.
You can modify subdocuments, but with features. This tip contains some of these features. You can modify subdocuments using the same tools that you have used to create a master document and subdocuments. This tip describes how to use those tools to modify subdocuments. How to create a master document, see The Master Document View, and Creating subdocuments for information about creating subdocuments.
Every master document consists of a normal document stuff and links to other documents. Those links can be used to pull in the information from the documents to which the master documented is linked.
If you work with several objects and have to move them or apply shared formatting to them, you must select these objects every time. Apply formal grouping and you will be able to operate those objects quickly as a unit.
By default, Word makes objects snap (jump) to an underlying grid laid across the document. If you drag an object, such as a shape, you'll notice that it moves in little jerks rather than smoothly. This is because of the grid - but because the grid is normally invisible, it's not obvious.