There are a number of beneficial insects and predators that you should know about that can help you with pollination, eating pests and preventing an unhealthy balance in your garden.
Here is a list of some (but definitely not all the extensive number) of beneficial insects and predators: Honeybee Bee Wasp Butterflies Dragonflies & Lizards
How to attract these creatures to your garden, provide:
Open soil (uncultivated soil)
Some shade
Flat saucers of water (butterflies and sometimes bees drink from)
Open flat flowers & Tubular flowers
Beware: Any sprays such as herbicides and insecticides, it is easy for the poisons to spread by the wind to where you don't want it ("drift"). These can also kill beneficial insects and also be detrimental to your health.