The style often recommended for new beginners to bonsai growing is the formal upright, or chokkan style. It is just a straight forward style that most resembles the tree in its full grown native state. So, what you’re trying to do is just to recreate the form of your bonsai tree in a suitably miniaturized version.
Basically, the form of the formal upright is erect, has a trunk that tapers towards the top, with symmetrical branches that have the spaces between them decreasing towards the top end of the tree. The formal upright style usually has a cone shaped form, but sometimes you will ones with rounded crowns.
This style lends itself best to species such as the Juniper, Spruce, and Pine, whose form naturally suits the regular formal upright style. Basically, conifers are best for the formal style, and even the California Redwood trees are considered to be ideal subjects.
The lowest branch is the largest and heaviest of all the branches, and often trained to point horizontally at an angle away from the viewer when viewed from the front, with the second branch and so forth, tapering towards the crown, thus assuming a Christmas tree like appearance.
The formal style becomes harder to achieve when you are intend to create a tapering trunk. This will require constant pruning of the top down while letting the bottom branches grow larger and thicker. Trunk tapering usually takes several years to achieve. Trim off the smaller branches at the lower reaches to achieve a consistent space between the branches that should be more or less even, while gradually decreasing towards the crown apex.
Though the formal upright style is more regular than other styles, it need not be planted directly in the center of the pot. Visual variety can be achieved by planting the bonsai plant a third from one end, either left or right as you face the tree.
The formal upright is considered the most classical of all the styles, and is usually meant to represent the “ideal tree”. In growing this style, bonsai artists try to create a tree that has perfect qualities not usually sustained in the natural wild.
Some bonsai artists prefer to develop a more natural style. In these cases, good visual effects can be achieved, like deliberately whithering the crown to show natural conditions like lightning strikes.
As the basis for creating other styles, the formal upright is the most flexible, robust, and generic, of all the styles in bonsai growing.