In the two Radiolab podcasts "Darkode" and "The Ceremony", the producers make exceptional use of conversation and sound effects to make an effective podcast. Part of what made the podcasts more interesting is that the people speaking are not really talking directly to the speaker, which is what I'm pretty sure most of us did in the podcasts we made. Instead, they had an actual conversation. I liked the Darkode episode especially because of this. The conversation also wasn't scripted, so the speech sounded normal and human, and not like it was written first. You could tell because the people speaking actually had to think about what they were going to say next, and because there were times in which they would hesitate or laugh in the middle of a sentence, which made it all sound very natural and appealing.
Another way in which these podcast were made more accessible was the way in which the producer told one long story throughout, and then branched off to explain certain parts of it. Each of these episodes really only revolved around a few topics, but they made sure to explain every detail of the things they talked about, which is what allowed them to create a 40-50 minute long podcast episode without running out of content.