We all know that and it is been well said that "the first impression is the best impression". The article that you write reflects your self, your understanding and best reflects what you want to convince your customer. Customer satisfaction solely depends on the contents of the article. Getting back to the best first impression, the whole gist of the article that you intend to write will depend on the very first sentence. The first sentence is responsible for lot more things.

It catches the attention of the reader.
It makes the reader stay and sustain in the article.
It creates the mood of the mindset that you want your customer or reader to have.

It generates the interest in the product.
It will create the platform in which the reader can build up his ideas about the product or service.

All these can be achieved only when, the start of the article is best at its own way. Every article is ought to be unique, so are the beginnings. Be careful about the connecting phrases. This may prove bad, if not considered. Start well, that is half done.