How do people choose which article to put on their site and which to use for Article Marketing?

What you do is put the articles on your site FIRST. Let them get indexed by the engines, give it about a month. Once indexed start submitting the articles to other directories or even slightly altering the article then submitting. While you wait you can submit your article link through http://www.digg.com to gain some exposer and link popularity. If you just alter your article after posting it on your site then your good to go at anytime for submitting to directories. Article marketing needs to be effective, therefor quality articles are necessary to grow your article throughout the web. Never consider a bad article to submit. Quality content is king for all aspects of online marketing.