New actors often ask how they can have more expression in their voices and avoid being monotone. The key is any good monologue performance is to show a variety of emotions.
When you go through a script, think of different emotions the character might be feeling.
Look at the monologue Protecto (Kid Hero). At first he is frustrated. Then he starts to get excited at "I love being a hero." Next he shows anger about a bully at school... "There's this kid at school..." Then he is playful when he talks about school lunch. Excitement builds again when talks about getting a catchphrase. But then at the end he is confused and having second thoughts. You'd want to reflect that in your voice and acting. Show each of those emotions for each part.
Next, look at each sentence. Pick out a word or two in each sentence that you'd want to put the most emphasis on. In the line "I've always dreamed of being a hero." You might pick "dreamed" or "hero" or both. Say these key words with more strength... say them a little more clearly or forcefully.
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