Here is a wonderful guided mediation from BexLife.com You can do this meditation either laying down in a comfortable position or in a traditional meditation pose or even sitting in a chair. The guide here says that this meditation is even good after a yoga workout.
Visualizing a sheet covering you, this guided meditation is good to help you get into a quiet space in your mind. Watch the video a couple of times to get the hang of it, then you simply do the meditation and visualize something else that works for you like she mentions at the end.
Try this meditation and let us know how it works for you. Has it helped you to relax?