what is the best way to get a job? i tried as a custodial officer but they said i was too skinny and young to get awarded the job but on the vacancy it said you have to be 18 or over and no qualification requirements needed 
That job is not meant for you, maybe that is their way to have a lot of applicants with their company. So that a lot of applicants will try to apply with them so they can choose who they want to get that will fit for their company. Try to some other company that needs new employee. That is not for you for sure there is a job that will fit for you.