Below are a few useful tips to keep in mind when creating your e-mail signature:

1. Keep it as short as you can while providing all of the information you deem most important (four lines is the accepted standard).
2. Condense information into fewer lines by using pipes (|) or colons (::) to separate the text.
3. It is best to have your signature in simple plain text; skip colors, special fonts and graphics. This shows better on mobile phones as well.
4. Use the accepted signature delimiter (--) to help your signature get recognized as such by email clients.
5. Be careful with HTML formatting because it may not appear how you want it to for everyone.
6. Test your signature with as many email clients as you can, especially if you use HTML.
7. Optimize your logo or other graphics, upload the files to your server, and use an absolute URL.
8. Provide written out URLs instead of using hyperlinks in your email to ensure the link will go through in the sent message.
9. Avoid listing multiple phone numbers and email addresses. Pick your contact preference and remove the rest.
10. Only include IM details and Skype account information if you want to be contacted that way by anyone who sees your message.
11. Skip your mailing address — not every recipient wants or should have access to that information.
12. Include your email address. You cannot rely on various email clients to include header information in replies and forwards.
13. Create different versions of your signature, both in length and content and know when to use each version (i.e. use a shorter version on replies).
14. Make sure you update your signature on your mobile device if you frequently use it to send messages.
15. Don’t attach your vCard to your messages. Not everyone uses them and even those that do don’t need to receive them repeatedly.
16. Reconsider including a quote; you never know when you might offend someone or give the wrong impression.
17. Do not include a legal disclaimer unless required to do so.
18. Do not include a virus-checked message at the bottom of every email.

To create an email signature in Outlook you must follow the steps below:

1. Once Outlook is open, select Tools | Options… from the menu.
2. Click on the Mail Format tab
3. Click on Signatures…
4. On the E-mail Signature tab you can click New and create a name for your signature. For example, you may want a long signature for New messages and a short signature for Replies/forwards.
5. Type your signature under “Edit Signature” as you would like it to appear at the bottom of your e-mails.
6. Once your signature appears the way you would like it to, click the Save button.
7. You can repeat steps 4-6 to create multiple e-mail signatures. Then you can choose the default signature to use for New messages and Replies/forwards.
8. Once you are satisfied with your signatures and have assigned them appropriately, click OK. Then click OK again.

To find more helpful tips on e-mail signature etiquette, go here.