welcome to healthcaremagic
females usually take time to be aroused
caress her fondle her
ask her what she likes and do that
whole body of female is site of attraction and of stimulation
pass quality time with your wife share her problems prepare her for the sex being nice caring and sharing daily chores
are you having small kids see to it you also take equal responsibilities rearing up the kid/kids
if she is tired give her good massage
be confident and talk frankly every thing will be all right

Hi Ameer Ali, Welcome to HealthcareMagic Forum.
Is she suffering from any illness or does she have any mental distress? there are lifestyle changes and sex techniques that may put her in the mood more often and sometimes medications. Kindly get her examined by a Gynecologist so that she can evaluate her completely and rule out the exact cause and if necessary refer her to a Sex therapist as she will need counseling. Does she have any pain while having sex? It could be related to Hormonal imbalance as well. She should be avoiding stress and maintain a Healthy a lifestyle. Ask her to exercise regularly and eat healthy nutritious balanced diet which should include fresh fruits and green leafy vegetables. Ask her to perform Kegel exercises, which can improve the awareness of the muscles involved in pleasurable sexual sensations and increase her libido. She should be performing it by contracting her Pelvic floor Muscles as if she is trying to control her Urine or stools. Communicate with her and resolve if you have any personal conflicts, set aside time for having sex, you can try to have it at different times and try different techniques every time, Try a different sexual position, a different time of day or a different location for sex. If you and your partner are open to experimentation, sex toys and fantasy can help rekindle your sexual life.

Wish you both Good Luck, Take Care.