Self-published eBooks shouldn't look any less professional than traditionally published eBooks. It's important to at least learn the basics of eBook formatting to make sure that the digital book you publish comes out on the other end of the eBook conversion process looking like something you cared about, labored over, and handled like a professional.
In order to turn your book into a functional eBook, your manuscript document (.doc, .docx, .txt, .rtf, .html, etc.) must be converted to another file format (ePUB for most eReading devices, and .mobi for Kindle).
Whether you're handling the technical aspects of this process yourself or having a service like BookBaby take care of it for you, there's a few things you need to do in advance to make sure your manuscript is optimally formatted for eBook file-conversion.
So you want to publish an eBook? Well, here's the good news: it's easy to do. However, you can't just push the "publish" button and call it a day.
That may be what other self-published authors are doing, but you've got to put some real thought and effort into your self-publishing strategy if you want your book to be successful. If you're truly going to act as your own publisher, then you need to step into the shoes of all the various publishing team members: author, editor, marketer, publicist, etc.