On what should i focus now ?

Hello people , i started HC marauder few days ago and made it to level 44 . Im focusing on elemental dmg using Lightining strike as my main move . Im at a point that im not quite sure what path to take on my passive tree .I use blood magic as a support gem because i like having auras but its getting really confusing for me on what passive nodes to take now .
http://www.pathofexile.com/passive-skill-tree/AAAAAgEAxthYY1BQjM_2SF8_VEnnUu8Oud3yL9SPGS4n7ayqcql82dlhVw1Z88AakFWnhBo47DhX4jKJd-UEs_AfAnEUTaIAqWjE9jwtxq7-CvJF52O3Pnq4bPauk6ZXOuGI8bXyqW4=

Sorry for not going into much detail but im playing this game for 3 days and stll experimenting with stuff . Im just confused on how to make my elemental dmg marauder work . Lightining strike does 750 dps at the moment with just 3 support gems(Life on hit , elemental weapon and blood magic) and i wonder if i should focus on taking those endurance charges + more elemental resists to increase survivability . Also i would like some advices for additional support gems on Lightining Strike and other active gems and auras that work well with the path i choosed to take ( I use Hatred and determination atm) .