Although children develop at different rates, the CDC (link): https://www.cdc.gov/ncbddd/actearly/milestones/index.html 
has published a list of milestones that children typically reach by certain ages. Review the CDC guidelines. 
Link: CDC guidelines: https://www.cdc.gov/ncbddd/actearly/milestones/index.html
Afterwards, use this milestone checklist : ATTACHED BELOW to create an activity for each age group that would appropriately foster social and emotional development. For example, read the suggestions under the section for 4 month olds. Then, think about what you can do at home or in school to foster appropriate social and emotional development in 6 month olds? Do this same thing for all of the ages groups (6 months – 5 years old).