Placing crystals in the home, office or any place you spend time can provide peace and harmony. You will find your guests staying longer, children fight less and there is less tension.
Amethyst provides good atmosphere and Rose Quartz for love (Always keep some in your bedroom)
If you finding things are not going quite right for you, or have jealous neighbours or friends - try placing some black Tourmaline at the entrance to the house, you most probably will find a big improvement over a few weeks.
In business you should keep Citrine cluster to improve your income. 
Go to my chapter in Crystals can be used for to see more uses of crystals