Here are some other faults I've noticed with received articles that can get them rejected.
Problems With Pen Names
Should you promote articles you've written on the various article sites around, you will more than likely find that these allow you to have a username, which you use to login, and one or more pen names, which are displayed as the articles author. Now, I've noticed a few faults here.
The initial fault usually happens when you already have an account at an article site, then join an article submission service such as Article Marketer. The submission service will create you a new account, and sometimes, if the pen name you use with the submission service is the same as one you already have at the site, you may end up with a blank as the submission services pen name, as the identical one is rejected. This means that the ability of search engines to spider your articles is greatly decreased, as there are no links to "More Articles By" or similar pages. Some directories will decline your article if this is the case.
Next, putting your website address as your pen name is often not appreciated either, so just don't do it. In fact, quite a number of directories will decline articles written by something other than First Name Last Name, so, although rules do alter from directory to directory, it's doubtful that any will decline to a pen name of, for example, "John Smith", whilst will decline or delete articles by "mysite.com" or "The Internet Marketer. Just stick with a standard name, even if it's not your actual one, and you will avoid any problems like this.
Poor Use of Article Spinners
You may not have come across services like these, or you may use something along these lines without realizing it. There are a number of variants around, but what they all have in common is that they are designed to take an article, and make a number of different variations of it. The variations may be only minor, but the concept is to create a number of "different" articles to avoid duplicate content penalties.
Now, there is nothing wrong with doing this, but there are wrong ways of doing it. If the spinner replaces words or phrases with variations, for example, "In the beginning" could also be phrased as "To start with", after doing this for an article and producing a number of variants, read each one through to make sure they still make sense. It's quite easy to produce gibberish if you don't, and most decent article directories don't like to publish gibberish. If an article needs tweaking, do so manually. Far better to make sure you spend a bit of time now on the article, then having to fix it after rejection.
The next problem is if you create a batch of 20 different articles, submit each article to a different directory. So, 20 articles to 20 sites. Or you could submit them to batches of sites, one article to 10 sites, the next to another 10 etc. Do not submit all 20 versions to one directory. They'll probably get rejected, and it's possible you'll lose your account for annoying the site owner.
Submission terms, and what an article site or directory will accept or reject do change, sometimes quite substantially, from site to site, but if you err on the side of caution, you'll get fewer articles rejected.