Horizontal spacing:

• letter-spacing
• word-spacing

body {
  /* H e l l o   w o r l d */
  letter-spacing: 1px;

  /* Hello      world */
  word-spacing: 5px;
}

• width

Ideal line length: between 50 - 70 characters per line

p {
  /* ch means characters */
  width: 50ch;
}