Do the easy things first, eliminate the pedals as a source of the noise. Borrow a set of pedals known to be quiet (from another bike, friend or whatever), clean and grease the pedal and crank threads, install and tighten firmly. See if this helps. If it does you are done, otherwise go on to the harder stuff. Also, make sure that the noise is not caused by the front derailleur cable end tapping the crank as it goes past.