Care is entirely supportive and directed toward symptoms. You are not running a greater risk by waiting to see what happens with your mild symptoms. If you have a severe, persistent headache, coupled with a very stiff neck, so that you cannot put your chin on your chest, then you should see a physician. If you are disoriented, cannot maintain your balance, or think properly, especially if you have a fever and a headache, then contact a physician right away. If you have mosquito bites, or have been in areas where you are likely to have been bitten, then your chance of exposure is higher.
Mosquitoes are most likely to bite at dusk and after dark, so take particular precautions then.
The West Nile virus, however, is also transmitted by one species of mosquito that is a day-biter. Be sensible, but don't panic. Take reasonable precautions against mosquito bites, but you don't need to hide in your room. Take sensible precautions, but remember that your chances of serious infection are extremely small.