The importance in planting trees and shrubs can't be over-stressed enough. More woody plants have failed in their first few years due to improper planting at the get go.

Site and water trees and shrubs well at the beginning, checking for two or three days after the initial planting for watering needs, and again every week for 6 months - 2 years and always weekly during summer drought.

Put a layer of 2-3 inches of mulch around the base, but 6 inches away from the trunk is best.

Stake the tree if it is in an exposed, windy location, but most of the time slight movement while growing is beneficial.

A tree with a well-developed root system does not usually need staking. 

More on planting tree and shrubs properly here. 

- Courtesy of NYBG Plant Information Service