What are some effective homemade mosquito trap outdoor ideas?

How about some very fine nylon netting, Amazon has it.

https://www.amazon.com/s?k=nylon+netting+fabric+by+the+yard&crid=50FWNZF7AWSQ&sprefix=nylon+netting%2Caps%2C1331&ref=nb_sb_ss_ts-doa-p_10_13

Place a fan or two on low. The mosquitos can't land in the breeze.

Hi Amy, hope these help you out.

Yeast & sugar

1. Cut off the top of an empty plastic bottle, cutting right below the neck.
2. In the bottom of the bottle, mix together a sugar and yeast solution (if using a 2 liter bottle, mix 1 cup of warm water, 4 tablespoons of sugar, and 1/3 teaspoon of yeast; for a smaller bottle, use the same ratio and adjust the amount accordingly).
3. Flip the top part of the bottle over so that it's pointed downwards and forms a funnel.
4. Place it on top of the bottom part of the bottle. Use tape or glue to hold the funnel in place, making sure that any gaps or openings around the edges are sealed.
5. Wrap the bottle in something black (leaving the top uncovered for mosquitoes to fly in) so that both the inside and outside are dark.
6. Refill the trap with fresh yeast and sugar every few days.

Soap and stagnant water females look for stagnant water to lay their eggs, when they land on the soapy water they will sink and drown

1. Fill a bowl or bucket with water.
2. Add a few drops of soap or liquid detergent and mix gently, without making it too bubbly.

Are you looking for the traps to be indoors or outdoors? I personally haven't had much success with any kind of trap and generally go for deterrence, making sure there's no standing water around, using mosquito coils and Thermacells outdoors.

In order to effectively trap mosquitoes on and around your property, combine sugar, yeast, and water. According to Timothy Wong, technical director of M&M Pest Control, "after a few hours, the yeast starts releasing a steady stream of carbon dioxide, which mosquitoes are highly attracted to."