When I am dictating into Dragon Naturally Speaking, I usually don't do it directly in front of the computer. I usually do it on my phone. For instance I may be taking a walk or driving and I'll just dictate something into my phone while recording it using a voice recorder app like Smart Voice Recorder for Android.
When I get back home I plug in my phone and let Dragon Naturally Speaking convert my voice recording into text.
What I like to do when I record my voice is speak as naturally as possible. What I like having Dragon Naturally Speaking do is I like to have it insert commas and periods automatically. That allows me to speak more naturally because I don't have to say "comma" or "period" while I'm dictating into my phone. And I don't even need to think about it.
You can set up Dragon to automatically insert commas and periods by going to the tools menu of Dragon Naturally speaking and clicking on the "Auto-Formatting Options" menu item. From there you'll see a little checkbox where it says "automatically add commas and periods". After you check that box, click "OK". Then Dragon Naturally Speaking will automatically add commas and periods for you. It does a pretty good job at it too.