Like said above, don't use Quick Shot. I only use it sometines on weak enemies to dispatch them quickly, when I don't have the patience to wait for another cast. It's a huge waste of energy.
Also Vital Shot can indeed spend a lot fo energy at the start of the fight, dropping it under 60, from where there's no return. Use it carefully. I actually prefer to spam Charged Burst instead, which seems to have much better DPS/Energy tradeoff.
Just add Flurry of Bolts once in a while when you're on <60 energy, and leave the damage dealing to Charged Burst and Aim Shot. This rotation is so simple that it seems newbish, but that's what you have to do until level 30 or so when you start to get more of the useful skills.