The real difference between a regular recording and professional audio is the fact that the latter has most probably been spruced up by an audio engineer. Unfortunately, audio engineers earn their chops over years through experience and knowledge. What does a first time podcaster do?
Short of hiring your own audio engineer, which costs more money, one option is to head online to services such as Auphonic. An automatic post-processing web service, Auphonic (which is also free) will bring your recording closer to professional audio standards.
Upload the audio file to Auphonic, after which the service then performs standard processes such as global loudness normalization, as well as audio restoration such as de-clipping and noise removal, to improve the quality of your recording.
Auphonic can also push the finished product directly onto sites such as YouTube and Soundcloud.