You can try to check the subject. Defferent behavior of subject uses hai, same behavior of defferent subject uses YE. I hope it could be helpful

很簡單 "還"用來表示同是第一人稱 A點了一個東西, A說: 我"還"要再一個東西(不管東西相不相同都可以) "也"用來表示第二人稱 A點了一個東西, B說: 我"也"要一個同樣的東西..... 但更精確點來說..."也"可以當"還" 來用 A點了一個東西, A說: 我"還"要再一個東西.....A也可以說我"也"要再一個東西 但"還"不可以當"也"來用 A點了一個東西, B不能說: 我"還"要一個同樣的東西.....

回锅肉 is delicious, by the way~

用你的例子来讲 我还要一瓶绿茶=I've had one bottle of it, I want another one. 我也要一杯绿茶=He had one. I also want one. --------------------- also 看两个句词 改为 "两个句子" 因为总是有太多人，还要排很久的对。有些人还会插队 改为 "总是有很多人, 要排很久的队。还有些人会插队" many people and a long queue sounds like one problem where people who jump the queues sound like another

也：also, too, as well. e.g. They visited some factories, also visited the school. 他们参观了工厂,也参观了这所学校。 还：in addition e.g. They visited some factories as well as the school. 他们参观了工厂,还参观了这所学校。 ------------------------------------------------------- "还"的其他意义: still, yet e.g. 排队的人还是很多 even more e.g. 今天比昨天还冷