The world of publishing has evolved tremendously in the last years, but still there are people that for some reason, have a negative perception about self publishing. Maybe it has to do with the fact that some self publishing authors make colossal mistakes that prevent their books from being taken seriously. If you want to be considered as a professional, successful author, you need to avoid these mistakes, before you start printing by yourself.
Designing the book yourself. That can be a huge headache, and if you're not a professional graphic designer, it would be best to hire one. Trying to design the book's interior and cover by yourself will only waste time and keep you from focusing on more important aspects. Even using a pre-made template to design the cover is not recommended because most readers judge a book by its cover. Most template covers will not look as professional as those custom designed covers.
Editing the book yourself. That's another really bad idea. Even if you are a great writer with vast knowledge about grammar and phrasing, you shouldn't edit your own work. You can easily miss mistakes because you are too familiar with the work. This task requires an objective professional, so don't hesitate about investing a bit more on this matter.
Rushing your book production. You are probably very anxious to publish your work, but you need to remember that producing a quality book takes time. It's best to be patient and not rush things – you'll thank yourself once you have a book to be proud of.