What is the most effective way to promote a collaboration on YouTube?

Producing a collaboration teaser uploaded to both channels is the most effective strategy because it generates early excitement and cross-promotes to both artists' existing audiences simultaneously. This maximizes visibility and anticipation before the main release. Using Google Trends keywords is good for SEO but doesn't create buzz or directly promote. Updating old video tags might bring some traffic but is less impactful than a dedicated teaser. Linking in other artists' comments is generally considered spammy and can negatively affect your channel's reputation.