The adult attention span is about 6 minutes. So, your students can only be expected to focus for so long.
Chunking or organizing content makes a huge difference in absorbing new information. Create a big picture first so students can better differentiate and compare more easily - helps them understand how things are organized more easily
Helpful to students to get a time estimate on chunks-best in 10-12 minute chunks. Since we tend to forget the middle of chunks, good to create a little overlap and also transition
To chunk: find the natural breaking points in a presentation then add transitions. A transition is a summary statement, a transition statement and an intro statement.
Next add support to reinforce content for each chunk such as a self quiz or a discussion. Look for areas where students are struggling and revisit those areas
Good metaphor - gallon of water is what we give, dixie cup is all students can handle at any given time. The gallon is buttermilk not Coke (i.e. - remember that the content isn't something the students are eager to get).
Do formative feedback throughout.
Do a few chunks at a time, but do it all the time.Source: Notes taken from a 2006 Impact conference in Chicago: "Chunking Content for Effective Learning", Robin M. Smith, PhD.