You may read the editorial of any major national english daily such as Hindu, Indian Express, Economic Times, Business standard, Financial Express, and Business Line.
You may also read articles in magazines such as the economist, the week, frontline.
Besides, there are other sources such as Arts and Letters Daily
Reading practice needs to be done with a pinch of salt. One must understand that his/her command over the language will not really change overnight. It requires a lot of hard work and perseverance. Unlike the other sections, getting better at RC will happen over a period of sustained practice.
You may also read the articles given below for more tips regarding preparing for VA-RC section.
You may go through many more articles by exploring the archives at InsideIIM by following the link below:
Hope it helps. Keep practicing. All the best !!