Maybe try to go defence tree with little Vigilance. Personally i have no problem with leveling my guard (i go defen. Sometimes i even beat down champions (4 lvl lower than me) only with my Kira.
You have some fine skills to use during the fight, but smoetimes You have to be quick (inerrupt is my bred and butter), force push - love it specially when now when reset cooldown for force leap. You have force stasis, bubble, etc, etc....
Guardians obwiously needs some burst but its a very ineresting class but its not easy mode