Before doing anything you must clean the bite area with plain water or rubbing alcohol.
Before starting I would like to say that as there is a huge discussion related to this topic so I'll stick to some simple solutions. If you need more then try this link:
Here - (as it got vast explanation)
1. Scotch tape:
Putting Scotch tape (or a bandage) on the bite will help remind you not to scratch, especially at night. If you scratch too hard, you could break the skin and introduce an infection.
2. Aloe vera
Aloe vera has anti-inflammatory properties, so this could help the itch
3. Listerine (Mouth Wash)
It has menthol, which cools the skin to help relieve itch.
4. Hand Sanitizer
It also works well as it can help you from itchiness.
5. Ice
Using ice for 10 - 20 minutes can help you and give relaxation.
6.Toothpaste
7. You can also use Honey.
But still avoid doing this as it can attract more insects.
8. Cloth
If you really got nothing means really nothing then simply take one cloth and blow some air on your cloth to make it little bit warm and then gently apply to your bite area. There you can feel little bit relax and keep doing it for 4 - 5 times till it makes you feel good.