The first thing you need to think about when under taking any decorating project is what colour and finish would be best to enhance the area you are planning on decorating. This is best achieved by applying different colours and finishes to different walls and seeing what works best where. Sample pots can be purchased from most DIY retailers or paint manufacturers.
After you have decided what colour and finish you require, the next step is preparation. As you may or may not know, without the correct preparation, the finished product will never be great no matter how many coats of paint are applied. Preparation includes every thing from removing wall paper that is no longer required to applying filler and caulk as and where it is required. It is usually beneficial to apply a mist coat to all bare plaster before using filler as the bare plaster tends to suck the moisture from the mix. After all the major problem areas have been filled and caulked, it is advisable to apply one coat of your chosen colour to all walls and ceilings before applying the final filler, this is because it is much easier to spot imperfections when all areas are a uniform colour.
Another thing to consider is what colour and finish you require the woodwork to be. If its bare wood or its previously been either stained or varnished, you could choose to use a stain again, providing that the colour you choose is either darker or the same colour as the wood that is already there. Some times it is possible to burn off or strip the stain but this is by no means guaranteed, whether it will be able to be stripped will depend on a lot of underlining factors such as what stain is currently on it and whether or not a wood dye has been applied previously. If you decide to use a paint instead of a woodstain, you can pretty much apply it over any surface providing the base materials are of a suitable condition.
Feature walls can really ad an injection of colour to a room for a relatively small cost, providing the feature wall is created using paint. Using wallpaper on a feature wall can create a really huge impact on any space and also has the added benefit of being able to add depth of space if applied correctly.