SHOW SOME EMOTIONS, DAMN IT!

A good book is a one that allows you to connect with the characters. Most writers do this by getting their readers to feel what their characters are feeling in the moment. There are several ways to do this, including:

Body language

Inner thought

Physical reactions

Memories

Dialogue

Body language – This one is quite powerful. Body language allows you to show the reader how your character feels instead of telling them.  

He slammed his fist down on the table.  

Her shoulders stooped and her eyes fixed on the ground.

Inner thought – This one is a useful tool for getting across emotions quickly. 

How could they do this to him? He wanted to hit something.

She didn't dare look up at the king, for fear of losing her head.

Physical reactions – This helps to get the reader close to your characters. This is the physical reaction your character has to an emotion.

His blood heated, his muscles tense readying to fight.
Dread settled in the pit of her stomach and her mouth went dry.

Memories – If you've set up a scene earlier in the book that has a similar emotion, or something similar has happened to your character in the past, then you may be able to use it to convey the emotions in the scene you're writing.

He couldn't believe this was happening again. At least this time  he was prepared to fight.

The image of her friend's execution flashed in her head, she did not want to die like that. 

Dialogue – This is a quick way to show the reader how the characters are feeling. Be careful, however, not to be blatant. "I'm angry" or "I'm afraid" aren't very interesting, nor do they sound realistic.

"How could you do this to me?" he asked. "I should beat you black and blue." 
"Please, don't hurt me," she said. "I promise I'll behave."

Try combinations of the above, and don't rely too heavily on one method alone. The main thing is to avoid telling your reader the exact emotion your characters are feeling. Instead, show them in any way you can think of. You'll find people will connect with your characters more and want to keep reading.