To send an email, click New in the toolbar or press ⌘-N. The New Message form, shown in Figure 19-6, opens. Here's how you go about writing a message:
In the "To:" field, type the recipient's email address.
If somebody is in your Address Book (Address Book), type the first couple of letters of the name or email address; Mail automatically completes the address. (If the first guess is wrong, type another letter or two until Mail revises its guess.)
If you find Mail constantly tries to autofill in the address of someone you don't really communicate with, you can zap that address from its memory by choosing Window→Previous Recipients. Click the undesired address, and then click Remove From List.
As in most dialog boxes, you can jump from blank to blank (from the "To:" field to the "Cc:" field, for example) by pressing the Tab key.