If you really want to improve your singing taking private vocal lessons is the best way to do so. Joining your school choir (if you are still in school) is another way.
Whenever I sing I sound like I'm talking. How can I sing normally ? Here is the link for you to listen to https://mfi.re/download/kxbl7ksxru9egmm/Voice007.amr Beware it will hurt you ears!