I have found that striving to achieve a sense of calm during standard meditation actually defeats the purpose. Putting too much thought and effort into releasing your worries and frustration is actually counterproductive. I know when I sit down with the intent to meditate by myself and without interruption, I often come away from the situation feeling more stressed out than had I not sat down to meditate at all. The act of trying to induce happiness has an opposite, unintended effect.
When I reflect on those moments that I have felt most at peace with myself, on a spiritual and emotional level, it becomes clear that it is because in those moments, I was allowing my thoughts to flow naturally without judgment or resistence. I was playing with my cats or sitting outside reveling at the beauty surrounding me. I was engaged in a thought-provoking conversation. I was dancing and letting the rhythm of the music inspire me. I was present, in the moment before me, soaking it in and allowing any particular thought to interfere. I was just being me and letting the present unfold itself.
My spirit had lifted to a higher, more secure place instantly, when I channeled my energy into the present moment. My heartbeat slowed and my breath followed suit. I was experiencing the wonderful effects of meditation, not by trying to achieve a sense of peace, but rather by meditating naturally; unconventionally. It is through participating in the present moment and living outside of your head that you will achieve an authentic sense of calm. It is by taking part in the here, the now, and the reality; it is by not focusing on the past and letting go of expectations you may have about the future, that you truly meditate without even trying.