You can easily create your favourite favicon by using a graphic programme which allows you to save the file with the extension .ico graphic files e.g. The GIMP. There are many online websites which provide the services to create a favicon for free; you just have to create an account on any such website in order to be able to create your own.
There are many graphic design professionals who provide their services online. You can hire them to create your own unique favicon. However, you will have to pay a particular amount of money for hiring the services.
It is extremely important for you to create a favicon that matches with the content and style of your blog. Otherwise, you will not be able to create an impression on the visitors. Moreover, the image should be clear so that it remains visible in the tabs and URL bar of the internet explorer.