1. Chokkan Style (Formal upright)

This is a most complex style with very specific rules for branch placement, pot selection and such. It is NOT a style for beginners, and even experienced artists approach this one with caution. Some of the sub-categories of uprights include:
Tachiki – (Informal upright, the style I feel suits most beginners), Hokidachi – (Broom Style),
Sabamiki – (Split Trunk),
Saramiki – (exposed trunk, the bark is MOSTLY stripped off) Sekijôju – (Root over Rock; the plant is grown over a rock and into the soil of a pot)
Ishitsuki – (planted in crevices in a rock) and
Neagari – (exposed root, like a mangrove)

2. Shakan Style (Slanting Style)

This style is fairly common and not too esoteric for the budding enthusiast. Some other similar styles include Bunjingi or Literati Style (a few branches at the top of a long slanted trunk, usually in a small, shallow pot), and Fukinagashi Style (Windswept Style, with all the branches coming off one side of the trunk).

3. Kengai Style

The Cascade Style is easily recognized as the trunk dips below the bottom of the pot. Two other styles that are offshoots are Dai Kengai, the formal cascade, where the first branch plunges down below the bottom of the pot, but the rest of the branching proceeds as a Formal upright, and Han Kengai, or Semi-cascade, where the trunk descends below the rim of the pot, often in a windswept style.

4. Bankan Style

The Twisted Style is probably closest to what came over from China; the Chinese are very fond of this style and often refer to them as “dragon” trees (In Feng Shui, the Green Dragon is an auspicious presence in the garden) especially in the East). The tree coils around itself like a Chinese dragon The secondary styles for this one include Nejikan, or partially twisted style where the trunk does not make a complete turn on itself, and the little seen Takzukuri Style, or Octopus, where even the branching is twisted on itself from a very distorted trunk

Outdoor bonsai position:

Generally try to keep the bonsai out of a position of direct sunlight, where they receive good air circulation, relative humidity, and are in a place where they are easily accessible to you for maintenance.

Water frequently:

Generally if you keep your trees outside where rain can water them, you don’t need to worry much in the winter except in times of hot weather or little rain. In the summer you should endeavour to water your plants several times a week, and daily in very hot periods – where you should move the trees into the shade.

Fertilizers:

The most common is pellet-form (such as ‘Osmocote’). This is a slow-release fertilizer which will take care of feeding requirements for several weeks at a time and is probably the type of fertilizer most used by bonsai enthusiasts. Soluble powder and liquid feeds are also used for rapid effect over short-term periods. These are applied to the soil with a watering can and are used up relatively quickly.

Best types of plants to use for bonsai:

Trees/shrubs which are used more commonly for bonsai – and adapt quite well are evergreens such as Pine, Cypress, Camelia, Azalea, Pomegranate, Holly, Serissa, Fig (Rainforest and Mediterranean) and Cedar. Deciduous trees such as Cherry, Maple (Japanese and Trident), Zelkova and Beech are also prime candidates.

Source: http://www.bonsaisite.com/mainten1.html