To control spacing between lines in a text element, select the text element and then drag the line spacing slider. For example, if you have a text page containing just a few sentences that run the full width of the page, consider opening up the line spacing to improve readability.
Similarly, you can use the character spacing slider to decrease or increase the space between characters. Large headlines can often benefit from a little bit of tightening. Conversely, with some fonts, adding a bit of space between characters can create an elegant look to a headline, especially one containing all capital letters. Again, a little goes a long way.