There are a few things you should consider before preparing a submission.
Requirements for an article to exist
In order for a Wikipedia article to exist on an organization, Wikipedia's guidelinesrequire there be at least two significant profile stories on the company in independent sources, such as established news outlets. These press articles should not be brief mentions, re-written press releases, executive appointments or news-of-the-day type articles. They should demonstrate a certain degree of investigative journalism or in-depth analysis. In practice, there are a lot of factors that may influence whether Wikipedians feel an article should exist, but in general there should be a very substantial body of source material to draw from in the press.
Neutral according to Wikipedia
You should consider thoughtfully if a neutral article (neutral according to Wikipedia) would benefit your client or employer. If the organization has a controversial or negative reputation in the media, Wikipedia will consider it neutral to mirror that. Also, if a marketing professional writes a promotional article where a negative one is more "representative of independent sources" editors will often over-compensate for the marketer's deception by turning the page into a borderline attack piece.
It is not unusual for a marketing professional to create an article, only to regret it later. The best approach is to be utterly neutral right from the get-go. If a "neutral" article by Wikipedia's standards reflects poorly, consider showing restraint. You're probably better off hoping nobody ever starts one.
Learn Wikipedia first
While editing Wikipedia is easy, learning how to do so well takes time. Wikipedia has hundreds of content policies and its writing style is different than what most writers are use to. It also requires Wiki markup coding to add citations, sections, infoboxes and basic formatting. You should consider avoiding submitting an article, unless you're willing to spend at least a few hours researching and writing the article, learning basic Wiki-code and navigating Wikipedia's processes. Strive to make an impeccable submission the first time around, because once it's rejected, Wikipedians will increasingly lean towards rejecting the article again in the future.
Will you keep an eye on it?
After the article is created, it will become outdated quickly. Anonymous editors may vandalize it. Brand antagonists will sometimes use poor sources to add bias negative material. In many cases the quality of the article degrades over time. Keep in mind you'll need to keep an eye on the article long-term and keep it updated.
Make sure to follow social media disclosure laws by disclosing your affiliation with the subject of the article at the top of your Articles for Creation submission. This way editors know that content is being offered by a marketing representative, rather than a crowd-sourced editor.