So let's begin with the number one way to lessen the presence of mosquitoes in your yard. Then if you want to read on feel free.
REMOVE MOSQUITO BREEDING AREAS.
Done deal. Here is a list of places to check and clean:
1) Clogged downspouts (Clean out those gutters).
2) Flush your bird bath every week or so
3) This is the big one. REMOVE OR EMPTY watering holding containers in the yard.
4) Correct poorly draining areas in the yard. Depressions, low spots, etc.
A note here about larger bodies of water and small decorative ones in your yard. In large areas of water there are natural predators to help control populations (dragonflies for example). The pretty little pond in your landscape cannot support that level of wildlife so you might check into bacterial insecticides at your local garden center or hardware store. These do not harm wildlife and have a 30 day effective life.
Also, although bat houses are always a great thing to install in your yard, bats do not feed enough to create a major impact on mosquito populations.
So you have done all the options above and you still can't stand being in the yard without being eaten alive. Before you call a company to apply a chemical control peruse the following notes:
1) Remember pesticides are not a long term solution.
2) Even if you spray your yard you can still have an issue from surrounding yards.
3) Hire a professional and KNOW what they are applying. Even if it says "natural" or "ingredients derived from chrysanthemums" they may still be using a synthetic pesticide such as pyrethroids which harm beneficial insects such as; ground beetles, honey bees, lady beetles, and lacewings. This product is also toxic to fish.
4) Lastly be aware of drift. The spray will drift even on a relatively still day. Are their children, dog bowls, bee hives, edibles, or any other living being that might be harmed by drift from your yard?
If you want even more info check out the link below and enjoy your yard in all its buggy wonder.