First start with your super run the class that you enjoy the most you will tend to do better with it. They all have there good and bad Parts. I like hunters for the most part but have leveled my titan the most. As for tips and tricks I would point you to Planet destiny's youtube channel they have good add vice. I'm not a great PvP player either so I do understand your problem my KD runs between .5 and 1.5 I look at it like this first and for most make it fun get with a group of like minded people go as a fire team this helps run with the better players and I do mean run follow them watch what they do. Watch your radar this is one of my worst parts I sit close to a large screen TV so it's hard to keep every thing in my field of vision. i wish you luck and hope your game time gets better where the ass hats are concerned.