The Didache (or, The Teaching of the Twelve Apostles), which some date around 50 to 120 A.D., has the following to say about baptism: 

“Concerning baptism, baptise thus: Having first rehearsed all these things, ‘baptise, in the Name of the Father and of the Son and of the Holy Spirit,’ in running water (εν ύδατι ζωντι); but if thou hast no running water, baptise in other water, and if thou canst not in cold, then in warm. But if thou hast neither, pour water three times on the head ‘ in the Name of the Father, Son and Holy Spirit.’ And before the baptism let the baptiser and him who is to be baptised fast, and any others who are able. And thou shalt bid him who is to be baptised to fast one or two days before" (Kirsopp Lake, trans. The Apostolic Fathers I [Loeb 24; Cambridge: Harvard University, 1912]).