I was reading the other day that the one new commandment Jesus gave us was not as I quoted in "Assumptions" (“love God with all your heart, soul, body etc”.) but is actually, "Love each other as I have loved you".
This is even better! It gives us a tangible picture of love - simple, powerful and all consuming. His love for us was total - full of mercy, grace, sacrifice, strength, comfort... so as we experience more of that love direct from him we just do it to everyone else.
One of my favourite thoughts: "Love God then do whatever you want" - awesomely, freeingly, scary stuff!