What's your process for interviewing guests?

• I research and create an outline with a list of questions but I do not provide them to the guest unless requested. This is to respect the guest's time and also to get more spontaneous answers. I have had a case where a guest read written answers which sounds very unnatural.
• Have a pre-conversation with the guest. Help them understand that it's not live so if they stumble over an answer, get stuck, or even just need to take a break that those things can all be edited out.
• To record I use zencastr.com but I have heard good things about squadcast.fm
• Level the audio. One person's recording should not be significantly louder or quieter than the other's or your listener is going to have to keep adjusting their volume to listen. You can take care of this yourself, hire an editor, or use an automated service like auphonic.com
• A lack of preparation can be a problem. Research the guest and have a list of questions already prepared. If you ever get stuck in the conversation then you'll have something to fall back on.
• Keep track of time. Check with the guest to see if they have a hard stop time. During the conversation, keep track of how much time you have left and how much material you still planned to cover.
• Pay attention to if an answer is going too long, it's a retread of a previous answer, or you are getting fatigued. If you as the host is bored, your listener will be too so think about how to redirect the conversation.

Not an expert, but have recorded about 50 episodes.

• I don't provide exact questions, but I have a pre-conversation to make sure I have a good "plan" for the episode. I set the expectation that I'll ask about the guest's journey, and then get into the "meat" of their book/theory/experience/whatever that will be useful to the audience. (Often the journey is the most useful part.)
• I bring a bottle of wine. This helps guests feel comfortable, and makes the episode sound like a conversation between friends catching up. Just having a good conversation is probably the best way to make folks comfortable.
• I have 2 ATR-2100 Mics and a Scarlet i2i mixer. For remote, I do Skype with Ecam Call Recorder. (I probably should look into Zencastr.)
• Lots of things. For me, this included audio quality (trying to share a mic, for example, editing my own audio). I was lucky to have a good idea of what I wanted to do and who I wanted to help, plus the wine thing makes it fun, but I've seen other folks launch a podcast without really knowing who they want to reach or why those people should listen. (Based on the name for your podcast, I don't think you'll have this problem.) Other than that, the warnings from @jjung and @csallen are spot on.

I don't provide a list of questions ahead of time, but I work hard to research good questions that the guest will be capable of answering well. I try to stick to their areas of expertise.

What really helps is a pre-interview. We talk casually several days/weeks before the episode, so that way then the episode comes, I know more about their style (are they long-winded? terse? strategy? storyteller?) and interests, and they're familiar with me and not nervous to talk. It feels like we're old friends who have a rapport already.

I use SquadCast to record. It's great. You get a local high-quality recording from the guest's side and video, so you can make eye contact and communicate subtle non-verbal cues. It makes the conversation more natural.

First timers imo…

• quit too early without giving their shows time to find traction
• don't set a clear goal for what success looks like for their show and why they're doing it, which also makes it easier to quit after a while
• don't properly research and prepare creative questions for their guests, and instead just ask generic questions that anybody could ask to anybody
• don't listen and ask follow-up questions enough, and instead stick to their predefined list of questions too much
• don't fully appreciate how important guest selection is — some people won't be good guests no matter how great your questions are
• aren't energetic or charismatic enough on the mic — audiences take their cues from you and won't be excited if you aren't excited (same with your guests)