Trees and shrubs that are especially close to a home need to be pruned. Overgrown trees and shrubs can damage the exterior of home especially when wind and rain can bang up against the home. Pruning is also healthy for your trees and shrubs, and allows you to create the desired shape of these landscape elements. Trees that are not pruned can become ugly, damaged, and pose more potential problems for the structure of the home.
The tools you need to prune a tree depend on how old and how big the tree is. Young saplings can be pruned with hand shears, medium sized trees with lopping shears, and larger trees with a telescoping tree pruner. Shrubs are usually pruned with hedge shears.
A lot also depends on the type of tree, especially different fruit trees. A large part of pruning is also personal preference over how you want your tree or shrubs to look in the context of your overall landscaping.
Here is one on pruning orange trees from eHowGarden.
Here is another one on pruning evergreen shrubs
The eHowGarden channel has a lot of great different videos for different types of trees. Click here to see them. http://www.youtube.com/user/ehowgarden/search?query=prune+tree