1  From the Dashboard, choose Design > Edit HTML.

Download a full copy of your template and save it somewhere save (just in case something goes wrong and you need to restore your blog).
3  Turn the Expand Widgets checkbox to ON (ie ticked)
Find this code in your template:
<b:include name=’feedLinks’/>
Remove it with this code:

Preview your blog, and it it’s ok, Save the change.

What you have done is to comment-out the code:  the “–>” is the “end of comment” command in HTML.
This approach is better than “hiding” the link by making it the same colour as your background (which could be seen as trying to hide things from the search-engines).  It won’t have any negative effect on your blog’s performance, and you can undo it very easily by moving the end-of-comment text back again.