^By just taking it slow in general. Not skipping conversations, reading codex entries, ...
I concur, and I'd add sifting through loot after a mission, distributing kit to companions and stashing the rest at the Keep, finding that the party chest is full so you have to sift through that stuff as well. Maybe start stuffing runes into weapons to conserve space. Levelling companions so that they can wear their new kit cannot be done at camp, so they have to be summoned elsewhere (but that is not possible at the Keep, for example). Stuff like that can easily eat up to half an hour after a mission.
Something like 40-50 hours including Awakening means 30-40 hours for Origins, and for a longest run that just doesn't look very plausible. A speedy repeat playthrough of Origins - without codex, skipping convos, solo hence no time spent on companions - probably takes 20 to 25 hours and that's with perfect precognition, optimised travel/questing schedule and finely honed combat abilities. For a first run it doesn't really wash.