Open YouTube
Sign in to your account
Go to the channel you want to unsubscribe from
Click or tap the Subscribed button
Confirm unsubscribe if prompted
Repeat for any other channels you want to remove from your subscriptions
On mobile, you can also go to Subscriptions, open a channel, and tap Subscribed to unsubscribe
On desktop, you can manage subscriptions from the Subscriptions page or your channel subscriptions list