When trying out the mattress, you should make sure that it supports your body well. Make sure that your spine remains in a straight line when you lie on your side. Test different lying positions and make sure that you are lying comfortably and do not feel any pressure points. Take enough time to get a feel for the mattress. Also check whether the mattress makes any noise when you move. Finally, you should make sure that the material is breathable so that you don't sweat.