[JSWolf]

If you are doing this on eBooks you plan to sell, you may want to not have paragraph spaces. Paragraph spaces can make it harder for some to read and 1em is rather large.

Here is what I put in and it works very well for <p>Some text.</p> It does not create paragraph spaces.

body {
  widows: 1;
  orphans: 1;
  margin-top: 0;
  margin-right: 0;
  margin-bottom: 0;
  margin-left: 0;
  text-align: justify;
}
p {
  margin-top: 0;
  margin-bottom: 0;
  text-indent: 1.2em;
}

If you are doing this for yourself, you may want to try a smaller bottom-margin such as 0.3em instead of 1em.