A Lotus Notes migration plan involves several key steps. First, assess the current environment and identify all data to be migrated. Next, choose a suitable migration tool, such as Shoviv or Quest, that supports Lotus Notes to the desired platform, like Microsoft 365. Prepare the data by cleaning and organizing it, ensuring no critical information is lost. Conduct a pilot migration to identify potential issues. Train users on the new system and provide support during the transition. Finally, perform the full migration, monitor the process closely, and address any post-migration issues to ensure a smooth transition.