One thing that helps immensly at lower levels before you can build up your stamina bar are the Stamina potions. You get one for free each day from the daily quests. Thanks to these nifty items you will be able to grind your way through even more stamina focused events. Whenever you feel like you might not be able to finish an event that relies on running maps (so Boss battle type events are exempt from this), always remember your good friend the Stamina potion