Example methods disclosed herein include accessing a secondary content schedule based on one or more watermarks detected in primary media content, the secondary content schedule to identify (i) one or more secondary content items and (ii) one or more first time values associated with the one or more secondary content items. Disclosed example methods also include comparing the one or more first time values associated with the one or more secondary content items in the secondary content schedule to second time values provided by a clock to determine whether to present a first one of the one or more secondary content items, the second time values based on a timestamp associated with the one or more watermarks detected in the primary media content. Disclosed example methods further include causing a media presentation device to display the first one of the secondary content items according to the secondary content schedule.