Decide what you want to say. This has a couple of variables. Do you want to highlight your current employment, personal life, skills, etc. For me I chose to use my name, position, company, social media links, and a quote that I really liked. It may be different for you, and you may have to fool around with a couple ideas before you come up with something you think encapsulates the real "you".
Get there in your settings. Instructions for: gmail, outlook, yahoo and aol. If you have another email provider I am sure that youtube has the instructions.
I chose to highlight my professional life in this format:
Now with gmail I have the option to turn pictures or words into links by highlighting them and clicking the link option. So I chose to link 4 of my social media outlets to my signature with the matching logo. I used iconfinder to find the icons I wanted in the right size for me. I used 16X16.
I found an awesome quote that works for just about anything I could be applying for and added it to the bottom of my signature.
The end result:
May your fingers rest from their weary googling.