- indent the first line of the paragraph by one-half inch
- do not indent, but leave extra space between paragraphs
Conveniently, we can set our word-processing programs to leave extra space after the hard return which tells the program that you are starting a new paragraph.
The current rule is to either indent or leave the space, but do not do both.
There is a popular style of writing blogs, business memos, letters, and reports called "Full Block." In this style, paragraphs are not indented. As you can see, I consistently leave a space between paragraphs rather than indent. Increasingly, everything we write is left- margin justified. There is always a blank space between paragraphs.
I have been, perhaps unnecessarily, encouraging my students to indent paragraphs for non-business writing. Most essay writing that they do for me is informal story-telling as they reflect on communication events in their lives. Indenting, rather that leaving the blank space sometimes means they can fit the whole story onto one page, but there is no particular other reason to indent. I imagine I am being anachronistic in preferring indentation for non-business writing. It tends to make the writing look more like the narrative story that it is and less like the business report/school assignment that it also is.
But the official non-rule is that the indentation sends the same message as the space between paragraphs. We must indicate a shift in perspective by starting a new paragraph. To fit a page, indent your paragraphs; otherwise, suit yourself and be consistent.