Toddlers learn be doing and the 'teachable moment' through play is your strongest ally at this age ... labeling their world for them in an authentic way to build language and so forth.

Reading, singing, finger plays and little games to do help foster turn taking and other social skills.

Social skills should be the focus at this age ... at least IMO they have all their little childhoods to learn their ABC and 123 but if they do not know how to be a NICE FRIEND it will do them little good