A good idea would be to do some research on your song. Find what it says, and if there is a spicy story to it, there are many sites on the net that will help you with that. Find some covers of it, and see how other people did it.
Focusing on you technique is fine, but don't over do it, this should bother you when you practice, not when you perform. When you know what your song is about, try to fit your self in those shoes, try to make the story your own, become the songwriter, or the narrator, or the hero of the song.
Lia Hide is a singer-songwriter, producer, music educator, and multi-instrumentalist. Her debut album was released by EMI, she then decided become an independent artist, besides that she wrote music for a Greek theatre. Lia performed in major festivals worldwide alongside acts like Tricky, Molly Nilson or Kovacs. She also studied piano, opera, musical theatre and popular music vocals, and songwriting and has been teaching these subjects since 2002.