Cliches are cliches because they are classic. Every story has them. The way to distinguish your story from the thousands out there that have the same basis is to put your own spin on the cliche and develop your characters and plot out your story to keep it coherent for readers-- too many subplots will have your readers scrambling to remember the facts and happenings- one or two subplots is plenty. lol
Writing natural sounding dialogue takes practice-- and most people are too self-criticizing. Just write out everything then after you are completely finished go back and try to read from a different perspective and edit as you see fits.