You can hand pollinate flowers using a small artist's brush. Insert the bristles of the brush into the flowers to gather pollen and then transfer that pollen to another flower.
Your problem may not be a lack of pollination. Pumpkin on a stick produces both male and female flowers, but at different times. The male flowers are produced first and then the female flowers. This is to prevent plants from pollinating themselves. If your weather has been unusually hot, the plants delay producing the female flowers resulting in only male flowers throughout your garden.
The other possibility is too much nitrogen in the soil. Nitrogen encourages the growth of foliage. If there is too much nitrogen in the soil. the plants will produce only foliage and male flowers, but not female flowers or fruit. You should have a soil test done in the fall.