Taking care of people around us gives me more happiness.
Since your question based on simplest things. I often used to be happy for very tiny things. Happiness lies everywhere but some people are searching it till end and dying without knowing it. Everyone have some ambition in life like want to be wealthy so working for it but not everyone can be topper so don't run for huge things in life.
Have a meal with your family members daily.
Spend few minutes for yourself
Act like child when you want
Life is too short make every moment beautiful one with simple things.