The best remedy is protection. Choose from a range of repellants to protect yourself from sandfly and mosquito bites.
If you are bitten then you can use a topical cream to take away the redness and itch. You can use a mild steroid cream like Egoderm 1% or Egoderm 0.5% or a non steroid cream like Eurax or Paraderm Plus depending on your preference. Paraderm Plus is especially effective if the skin has been broken as it has an antiseptic property
If you have been bitten all over then an oral antihistamine like Zyrtec, Claratine or Telfast will be effective.