how to make a letter of resignation

how to make a letter of resignationTo tired to staying here.No one speaking with me causing there are only three.My boss.My Trade manager and I,I don't know how to controll this realationship with each.I'm only a clerk not a god.I can't do every thing right but I will try my best to do it well.There is no used to speak any more.Causing I want to quit this job.Maybe next time I will haven't this lucky.So I hope you can give me some good suggestions and advices to writting a letter of resignation.Your kindly answer will be appreciated.