I've been playing for about four years, and I've never found an opening where double tonguing is completely necessary. I'm a freshman in high school (almost a sophomore, exams are this week). I've tried learning to double tongue, and though I'm better than some of my peers who've made less effort, there's still a hesitant gap in my air flow and a harsh attack that I hate. I know I'll have to learn it at some point to get as far as I want to, and I want to know how to do it. I was wondering if I should be making this a priority right now. By when should I know how to do this? And can anyone give me some advice to help me learn this technique better?