This information is for users of the Apple Mail App that process copious amounts of email each day. I am not quite in that category, but I do go through an above average quantity of email. If this is you, then it may be in your best interest to use the Mail App in Full-Screen. That way you can block everything else out and focus on processing lots of email. Lets take a look at Mail Full-Screen.
If you do a ton of email everyday, you may prefer to work in Full-Screen View. Here is the Mail App Full-Screen view:
I am doing these images on a 27” iMac so the writing may look a little small. Here is the cool thing in Mail Full-Screen View. As you are working on you’re email your may need to write a reply or just create a new email. When you click on the Compose New Mail icon you get this side by side screen (split view):
This is a very handy way to work with email. You have the mail composition window open and ready. You can go through email and send or reply to messages as you go along. It really is a good way to power through a bunch of email.
There is another thing I want you to consider. You can click on that center divider line and drag left or right:
For example, you can have a larger left pane for reading email and a smaller right pane for writing emails, or conversely. If you are a email power user, this should appeal to you.
I use Postbox primarily to manage my email. It does not have this feature although it has other redeeming qualities. Maybe it will be implemented in the upcoming Postbox 6.
If you are a Mail App power user you might try the Split-Screen View. I think it would be a great way to manage your email workflow.