I've covered this subject before (see Are You Intoxicated by Your Own Verbosity?), but I constantly find more examples.
Sometimes authors like to use more words, or bigger words, than are necessary for expressing a point. A good
editor will know what to look for to cut extraneous words and streamline the prose without compromising the message.
In other words, don't use a big word when a minuscule one will suffice. Consider the following:
In regards to can be changed to regarding or concerning. Or anything, really. Please don't leave it as in regards to.
Due to the fact that is just a wordy way of saying because.
In order to, when it begins a sentence, can be cut to simply To.
These are just a few examples. There are countless others. When you see big words or more words than are necessary, consider what you can do to cut the fat and make the author's message more prominent.