Not as a DMGM , but as some one about to run their first One Shot as well . The advice I got was 1 Over prepare every conceivable outcome . Don ' t worry about over preparing backstories or NPC shops . I mean your players may sideline your entire Quest . And than you ' ll have two options . Railroad them . Or say you don ' t have any idea and neither are fun . 2 Study the rules like others have said but don ' t stop the game for it . House rules it and than after session look it up and make notes . 3 Ask your players beforehand what each of them would like from the adventure . Take pieces of that and it ' ll help build your story in return . While giving the players personable stuff . 4 Remember that DM is or should be a job that is recognized as a burdenhard job . Your players should realize you ' re new and it takes a lot to do . So don ' t or try not to be nervous . They understand . 5 My own personal tidbit or thing I most want to see from DM . Be flexible with the way things can attained . If I don ' t want to pay that Silver amount and I ask to work off the stay in the inn instead . Be cool with it . This is actually how we had a total unplanned side portion of one of our players trying to hide a murdered body that they found while doing cleaning . And a street fight with a Tiefling player where she brutally took out the murderer