When it comes to decorating a wooden object, any one of a number of techniques may be chosen. Some may be applied to other materials, but most are specifically for treating wood. Here's a run-through some of the most significant:

A) Water-based
Hues: These can be liquid or powder-based, and come in a variety of colours. Apply a single hand with a brush. Leave to dry, polish with fine sandpaper and add several hands of 50% diluted primer. Finally apply a thin layer of wax or matt varnish to protect the wood and, if you wish, decorate with watercolours and/or acrylic paints.
Stripping: Sandpaper the wood and apply a hand of primer. Then apply two layers of acrylic paint of your choosing. Once dry, sandpaper once more with care and apply two more layers of acrylic paint of a different colour. Leave to dry and sandpaper with paper dipped in soapy water removing the base colour. In this manner the grain effect with both colours is achieved. To bring out the wood's pattern, paint on a decoration with fine acrylic or oil-based paint. Finally, add a little wax or varnish or primer.
Stencil: Consists in painting over a stencil to decorate all types of surfaces and objects. The stencil can be made manually although it is usual to purchase it in a specialised store. Fix it on to the surface to be decorated with sellotape and paint over with a roller or paintbrush dipped in the chosen colour. Once done, remove the stencil carefully and give it a hand of varnish to protect the colours.
Cracked effect: This technique gives the surface a cracked appearance. To prepare the wood apply two hands of primer, sandpapering the surface after applying each layer. Then apply two layers of acrylic paint of your chosen colour, and later a hand of latex crackling. Finally, paint on another hand of paint before the surface begins to crack and reveal the base colour. To achieve a more attractive result, the wood can be decorated with oil or acrylic-based paints.
Sponge effect: Prepare the wood with a layer of white plastic paint and leave to dry for half an hour. Sandpaper, remove the dust and add a layer of water-based paint, which will act as a base. Once dry, dip the sponge in the chosen paint and apply by dabbing. To finish, apply a layer of varnish.

B) Oil-based:
Sponge effect: Prepare the surface with two hands of sealer and smooth with a fine sandpaper. Apply two hands of enamel in your chose colour (preferably white) and sandpaper once more. Prepare the paint by mixing it with varnish.
The technique can be applied in two ways: wetting the sponge with water and dabbing small splashes of colour on to the surface or applying the paint with a brush and later dabbing with a wet sponge to create texture. In both cases, leave to dry once finished and add a layer of satin varnish.
Dry cloths, plastic cloths or silk paper: Prepare the surface as above and apply the oil paint with varnish in a rough fashion with a brush. Then dab with the dry cloth, plastic cloth or silk paper depending on the effect desired. Leave to dry and apply a layer of satin varnish. This technique is an ideal way of imitating marble and stone.
Faded colour effect: A perfect technique for wood with heavy grain. Choose the colour and mix with varnish (around 45%) and turpentine (50%). The paint should thus be well diluted to prevent it from drying too quickly. Apply a layer with a wide brush in the direction of the grain. Then rub the wood again in the direction of the grain to remove the paint. Once dry, you can add another colour and repeat.