One of the things I took away from my web design days, was that although people like to use generic buzzwords, they almost always have something specific in mind that deviates from whatever standard would typically be applied to the generic buzzword they used.
In other words, I don't know what you call "professional". So.... here is what you do. You find blogs that look like what you want YOURS to look like. Then you modify yours to adopt that style. It would be best if you customize it afterwards, to personalize your choice.
Many blogs use templates... meaning they pick one of the standard templates. Have you looked through the options available to you? Most likely the choice of blog backend you decided to go with has the ability to switch between several designs. Do you not like any of them?
Where do you believe you have problems? What makes you believe it is not professional enough? I am not saying either way. I am asking you questions.