You need a plan. It doesn't have to be firm or detailed. But you probably need to have some idea of a direction you want to go with this frame. Do you want a thin wheeled racer with modern brifters? Do you want a straight bar, upright, city beater? Do you want a sturdy tourer with bar end shifters and racks? Do you want to restore it close to original? Maybe build a single speed (does it have horizontal rear drops)?