When I was little I liked to sing primary songs. 'I Am a Child of God' was one of my favorites and it still is. I still sing this song. Sometimes on days that are especially hard, I'll sing this song to myself and instantly feel His love which calms me down, brings peace and helps me focus on what's important.
link to video: http://www.youtube.com/watch?v=gv4n2qVsme4&feature=player_embedded