How can I influence a reference which I think unfair?

I am thinking of going to college next year poss to do nursing or childcare etc.I know which one I want to go to.However I have been in trouble abit at school nothing major jus swearing and dissing but the last was a misunderstanding.My teachers have had a go at times but I think I am misunderstood,they mentioned that with my record not to be expecting a good reference,this is unfair as it will hamper my chances