The first step in controlling a mosquito problem is to remove any unnecessary still water sources on your property. This will help lower mosquito reproduction and hopefully reduce their numbers locally.
Another potential aid is a mosquito repellent; two commonly used products are 'musca-ban' spray and 'fly repella' ointment - both should be used as directed on the packaging as required. Products like 'Aerogard' are toxic to many animals, including dogs and cats, and should be avoided at all times.
'Advantix' is a monthly topical application that can also be used to help deter mosquitoes and sandflies. The main caution with this product is that it shouldn't be used in households/on properties where cats reside and it should never be used directly on cats; some ingredients in this product are toxic to them. When used appropriately on dogs, 'Advantix' can work very well at deterring mosquitoes and is a convenient alternative to repellants.