You'll find your Notifications in the Activity Shelf in Buckets. This is where you can manage your System Notifications Subscriptions.
Open the Settings (the gear icon) in your Notifications feed and click on System Notification Subscriptions to choose which Notifications you wish to be alerted to.
If you want to remain a member of a Project without getting notified every time someone else adds an update, you can opt out of Project Member Updates. The same applies to items within Cards such as; Notes, Checklists, Comments, Attachments, etc.