Here is how I did it and would go about it today. Look for “needs” in your neighbourhood and offer to provide them.
You see a lawn full of weeds? Place an offer: “I will make your lawn look perfect for $20” (or whatever the traffic will bear don’t be afraid to set price high and then negotiate. You can always go down in your price. Never up. At least not till you get to the next customer.
Dirty windows? “I will wash them for $5, you can pay me after I have done a good job.”
“Car wash needed?” ask for $10. Full “detailing” with wash and polish with interior plastic and leather treated, etc. $50.
”Dogs walked?” that will cost $10.
“Kids taken to and picked up from school?” That will be $10 per one way trip.
Earning an extra few hundred cash a month this way is very realistic. Better than a part time job. You have to figure out what to try in order to reach your goals. Then try it.