Think of everyday situations that people can relate to and exaggerate it, find inspiration in all aspects of life, we all have one family member who thinks they are better than the family sort of thing, we all have that friend who talks rubbish etc,
One I used is awkward moments and embarrassing situations such as realising you are walking the wrong way and instead of just turning round you have to do something like looking at your phone so you don't look mental.
think of the funniest things that have happened to you and add to it and exaggerate it.
An amusing sketch you could use that I wrote a while back and never used, If you can be bothered would be;
2 horses taking as a Japanese car comes past, they look at each other and one says "damn foreigners, coming here and taking out jobs"
its short, clever and amusing.
I hope this helps!