You need to have Invitation letter/hotel booking, return air ticket, bank statements of past 6 months, Travel Insurance of Euros 30,000, One colour passport photo 35x47 mm size. Schengen visa application form:
http://www.immihelp.com/visas/schengenvisa/application_form_english.pdf

Other documents can be requested by the embassy, depends on which embassy you are going to apply.