Time to time in ISC, the webmaster will be giving a forum notice asking the interested people to give their names for premium content writing and in that case some members also apply for the same whenever such an opportunity arises. This is basically for those who have a very good grip on content writing and can deliver elaborate work on the given topic or theme in the stipulated time frame. This content writing thing is also happening in many other sites in internet under the different projects or names of the scheme.
Anyway, if a person is interested in such a premium segment work he can interact with the webmaster through ISC or webmaster's email to find out if any such opportunity exists at the present juncture. It will also be advisable to forwards one's credentials in this area for the consideration of the webmaster so that if he finds a deserving case, he can give a positive response on that.
Knowledge is power.