Changing to another school

First you have not told me the school banding and your academic ability. What I can do is I try my best to prepare the most updated information about the Banding of each Kwun Tong Disrict secondary school as follows:

聖傑靈女子中學 ---- Top Band 1
觀塘瑪利諾書院 ---- Top - Middle Band 1
聖言中學 ---- Middle Band 1
觀塘官立中學 ---- Middle Band 1
福建中學 ---- Middle Band 1
藍田聖保祿中學 ---- Bottom Band 1
中華基督教會蒙民偉書院 ---- Bottom Band 1
梁式芝書院 ---- Top Band 2
新生命教育協會呂郭碧鳳中學 ---- Top Band 2
順利天主教中學 ---- Middle Band 2
滙基書院（東九龍） ---- Middle Band 2
聖安當女書院 ---- Middle Band 2
聖若瑟英文中學 ---- Middle Band 2
聖公會梁季彝中學 ---- Middle Band 2
仁濟醫院羅陳楚思中學 ---- Middle Band 2
五邑司徒浩中學 ---- Middle Band 2
基督教聖約教會堅樂中學 ---- Middle Band 2
中華基督教會基智中學 ---- Bottom Band 2
基督教臻美黃乾亨小學暨初中學校 ---- Bottom Band 2
聖公會基孝中學 ---- Bottom Band 2
寧波第二中學 ---- Middle Band 2 - Top Band 3
寧波公學 ---- Top Band 3
基督教中國佈道會聖道迦南書院 ---- Band 3

You have not told the gender here so I cannot select the appropriate one for you, but if you are from a Band 2 school, you can focus on those better Band 2 schools as mentioned. If you come from a Band 3 school but the result is much better than schoolmates, you can attempt those lower Band 2 schools, etc.

But I want to highlight that since you are Form 5 now, it is hard for aided / government schools to accept you as a Form 6 student directly. A repeat is nearly a must. If you do not want repeating, the chance of transfer is small. So in this case, would you consider attend those famous private tutorials after school for examination techniques and focus-learning to maximize your results shortly? This can avoid your waste of school year as mentioned.

Hope I can help you to explain the situation clearly.