You may have good idea regarding optimisation techniques but do you have the time and patience to do all those link buildings? If the answer is yes, then go ahead and do it yourself. But, if you answer on negatively, it is better to hire an optimization firm for serving your purpose. They will cost you some extra cash but if you find the most suitable farm; the results will be amazing. It is better not to use any automated or semi automated service, as pretty often they are not of any use.