A subscriber is a person who expects another video
Sub-for-sub, bought subscribers, and pods create a number without an audience. The next upload is judged by people who never wanted it. Skip those. Make the last video recognizable enough that a stranger can describe what you will post next.
The longer version of the 1,000-subscriber path is in the subscriber guide. Confirm monetization thresholds in Studio. This page is about the behavior, not a forecast.
Point at a next watch
Put the video they just finished into a playlist named after the promise, and link that playlist in the description. The playlist guide covers the order. End screens are set in Studio. The public API cannot see them.
Fix the title that hides the series
Episode numbers and inside jokes assume a subscriber you do not have yet. Lead with the payoff. Use the title generator if you want a few wordings to compare, then keep the one the video actually delivers.
Measure with your own uploads
Compare public view counts on the videos in one series. The one that traveled is the format to repeat. Creator Climb does not predict how many subscribers the next upload will add. Paid plans save the audit and the month of titles so the series stays visible to you.