Start of series: funny, occasionally amusing, it will brighten things up (8)
I believe the answer is:
sunlight
'it will brighten things up' is the definition.
The definition suggests a singular noun which matches the answer.
'start of series funny occasionally amusing' is the wordplay.
'start of' indicates taking the first letters.
'occasionally' indicates alternate letters.
'amusing' becomes 'light' (I've seen this before).
The first letter of 'series' is 's'.
The alternating letters of 'funny' are 'un'.
's'+'un'+'light'='SUNLIGHT'
Can you help me to learn more?
(Other definitions for sunlight that I've seen before include "What's illuminating, naturally" , "Possible reason why blinking" , "Ray" , "Solar illumination" , "Solar radiation" .)