CV and Covering Letter

I am currently writing the covering letter for my CV, and never thought it could be this tricky. Making the covering letter interesting and readable is hard enough, but doing this while not sounding generic is quite difficult. I have been using http://jobs.guardian.co.uk/cv.html  to give me advice on writing my CV and covering letter. I have found this site to be very helpful, and hopefully it will allow me to be successful in writing the rest of my CV.