You might not believe this at the moment, but knowing how to control spacing issues in InDesign is probably the most important difference between a project that looks amateurish and one that appears professional. Spacing includes the space between letters, between lines, between paragraphs, and between elements. Inappropriate or unconscious letterspacing can make type difficult to read, difficult to comprehend, and difficult to respect.
There is no formulaic method for adjusting the spacing—it is entirely dependent on the typeface, the type size, the paper, the color of ink, the purpose of the piece. The final judge is your eyes. Your eyes know if the spacing is uneven, too tight, or too loose.
Listen to your eyes.
That is, ...