I used to memorise passages of Scripture by writing them out by hand, carrying them around with me and practice reciting them. At one stage I memorised the whole sermon on the mount (Matthew 5-7). Even though I can't remember the passage word for word any more, I have a good idea what these chapters are about - it stuck really well. Why don't you try to memorise a passage or even a whole chapter? Perhaps start with a Psalm or something from the New Testament.
Short and sweet inspirations for Christian teen girls.