The Siri User Guide has posted a killer guide that will help you better control Siri when you're dictating. For instance, when you're dictating to Siri, saying "all caps" in the middle of your spiel will cause the next word to be in all-caps while leaving out the actual command. So, saying "I all caps love summer" will result in "I LOVE summer." There are 59 entires in the Siri Dictation Guide, and it's very handy. Check it out.
Check It Out: Learn How to Control Siri with the Siri Dictation Guide