Forwarding emails to Evernote to turn them into notes is one of Evernote's awesome features. However, if you want those notes tagged or in a specific notebook, you have to adjust the subject line. A much easier and faster method is to use this Google Apps Script with Gmail.
Web developer Harry Oosterveen developed this awesome script, which forwards emails to Evernote at regular intervals. The video above shows how quick it is to add the tags you want and send the email to a specific Evernote notebook by dragging-and-dropping the Gmail labels to the message.
To set up the script yourself, make a copy of it (go to File > Make a copy...) and add a trigger that will specify how often you want the script to run. That's it.
You can also add default tags and access a log sheet in case of troubleshooting.
Although you can also auto-send Gmail messages by label to Evernote using If This Then That (IFTT), you have to set up multiple recipes to do that. This script is a lot more flexible. Combined with automatic message filtering, it can save you a bunch of time if you're an Evernote user.
See the full instructions at Harry's site below.
Send Google Mail to Evernote | HarryOnline