Even if all mosquito breeding is eliminated in one area, new members from another area can fly in to feed. Spraying or fogging around your property can provide some temporary relief from biting adults, and may not be a bad idea if you are going to have an outdoor event. Any sources of stagnant water should be eliminated weekly. This can be done by simply emptying them, changing the water, or disposing of containers. This will at least keep them from breeding on your property.
Many repellant products are available for adult mosquitoes.
Some repellants can be applied to the skin to keep them from biting, while others may be designed to keep them away from an outside area. In some areas where mosquito populations are high, people will build screened enclosures so they can be outside in peace.