If you can post your full build (including sigils, runes, jewels) we can probably be more help.
Also, maybe try a video in sPvP so we can get a better feel with a more level playing field.
Going with what I saw, you might want to consider trying to get some combos going, to stack up a bit of might. When you opened up at the beginning of the video you go from fire to earth but didn’t drop Fire 4 to get the might from Earth 4 that you then used. You can also go right into Earth 5 and then either get some more might or use teleport to land it if they run out of the blast. That sort of thing.