Here are a few ideas from the experts:
Thunderbird enables you to have multiple sets of folders. Each email account can have its own inbox, and sets of folders or accounts can share folders.
You can label a message in Thunderbird to indicate which type of message it is, including personal, work-related, important, or a task you want to do at a later time.
By filtering messages, you can automatically process messages, file them into folders, and perform other actions on your incoming email.
With message sorting and grouping, you can order your messages and group them into logical groupings.
Thunderbird has a powerful and flexible search feature. This search lets you quickly find information in emails.
With Thunderbird's search folders, you have a way to save a search and reuse it at a later time. Search folders are dynamically updated as new email arrives.
You can delete a message's attachment leaving the message body intact. This keeps your mail box size in check, while allowing you to keep a historical copy of the message.
Your Thunderbird address books enable you to organize your addresses and other useful information such as telephone numbers and even some custom information.