A variation in music genres. Maybe start with some techno, go into some alternative, then some hiphop. You don't have to play entire songs but music is very important in pk vids.
I would love to watch it =)
I'm always interested in any video on runescape
To me watching people play is more enjoyable then playing idk why
Some obvious tips
Get some high loot kills in the video
Get some amazing near death experiences
Show a death or two of your self =) They always spice it up
And just go around owning people!