If you looking for buttons and banner images to promote your YouTube channel, just head over to this page and download the ones that will look good on your website or email newsletter.
You can link to your YouTube page in two ways:
A: Link to the main channel – The user will see all your recently uploaded videos and your favorites and he will have to click the “Subscribe” button in order to subscribe to your channel. See example:
B: Link to the subscription page – The user can directly subscribe to your YouTube channel after clicking that confirmation button though he won’t necessary see your YouTube page. See example:

The graphics are available in all popular sizes so you may even use them as stickers or print one on your business card.