You should have a reputed online presence in the degree you desire to teach. Publishing online articles, blogs, and participation in professional online communities in relation to academia will enhance your resume.
The online teaching environment is different from a traditional learning environment. You must be able to speak and write well. You will be required to give frequent feedback and communication through lectures, discussions, assignments, and grading and critique. Highlight your attributes in these areas.
You also need to be technologically adept as courses are delivered in an asynchronous, Web-based mode. Reliable, high-speed Internet, good typing skills and a computer with significant enough memory to support the software for the course are necessary. Flexibility is a must as computer glitches happen.
You may be required to include with your CSV letters of recommendations, a teaching philosophy, a sample of a syllabus you have created, and your academic transcripts so have these ready to go before you start applying.
As with any employment position, do your homework. You want to know about the college history and philosophy, their degree offerings and the position offered.