This will help if you are a new podcaster.
1/ Run ads on podcast apps like Buzzsprout, Overcast, and Pocket, or use the ad platforms of players like Spotify.
2/ Sponsor niche-based newsletters. This is a great way to get your podcast in front of those who are interested in the exact topic you talk about in your podcast.
3/ Cross-promotion on related podcasts. Get in touch with those who run a podcast that is related to your focus area and then offer to promote their podcast on yours while they do the same for your podcast.
4/ This one is for podcasts that do both audio and video. In such a scenario, the best way to cross-promote your podcast via audio and video is to promote video in audio and audio in the video. So in the middle of the audio podcast, mention something like – “do you know this podcast is also available as a video on YouTube? Find it by searching [mention your podcast name] on YouTube.” Same for audio promotion on video. Say something like – “do you know this podcast is also available in audio format? It is linked below in the description.”
Hope this helps. Also, let me know what you think and if you have any questions.