First identify the overall look you want to achieve, such as contemporary, minimalist or classic. A lot of people will start off by painting their walls, not really knowing where to go from there. I often suggest that my clients look through magazines to get ideas of things they'd like. It may be as simple as choosing a lamp you like and starting from there. You have to have a style that you can live with.
Establish the effect that natural light has on your room throughout the day, as it changes all the time. You also need to consider the artificial light you use during the evening. Remember, we have long grey winters, so the room you paint in the summer will look different during the darker months.
Be aware of your home as a whole and try to achieve a colour balance between the rooms. You don't want two colours that jar with each other as you go from, say, the sittingroom into the hallway.
Do not be afraid to use several variants of one tone to create interest. At the moment, shades of white and cream are fashionable. To mix shades you can select taupes, rusts and beiges, and use one on the walls and others on the coping, skirting and ceiling. With light colours it is tempting to paint everything one colour, a trend started by Kelly Hoppen, but several shades look better. It is actually better to use a number of tones. Two shades of blue in a room can clash but three, four or five will work well. Often people think of blue as a cold colour but if you choose a nice dusky blue with depth it can have a warmth you won't get with navy or a very pale blue.
When choosing a colour, spend a lot of time on research. There are many variations of cream and white at the moment and you need to seek out clean and crisp shades. If you get it wrong, you will end up with a mushroomy or peachy tone and that Burma Buff you selected will turn out to be plain old magnolia. Really look at the colours and get samples.
The colour you choose for your room should incorporate all the details of the space. The walls (and flooring) act as a backdrop to everything in the room, including art, fabric and furniture. Consider the room as a whole.
Sample pots are a must. People are reluctant to invest time and money in these but it is definitely worth paying £10 to get the colour right. Colour cards are so tiny and most don't even use real paint - the colour is printed on - so it won't be accurate. Invest in a sample and paint it on to a large piece of board. Place it around the room during the day and evening to see the effect that the changing light has on the colour. I spend the most time on this stage and take ages to make the decision.
When you are working in a small room, it is often better to acknowledge that it is just that. You should make something of a small space. I don't often use wallpaper or paint effects but might do in this case, perhaps turning it into a small cave or something interesting by going mad with colour. If you paint a small space in cream it won't look bigger. The same goes for small furniture; you should just put normal sized furniture into a tiny room.
If you are hesitant about using strong colours, paint just one wall in that colour to create a modern and dramatic effect. Keep the other walls white to create a backdrop.
There are no hard and fast rules to choosing colour, although interiors are almost following fashion at the moment. Perhaps it is easier now that whites are "in", but there was a lot of colour around a couple of years back and people were very nervous about using it. I tell clients not to phone me in a panic when the room is half painted. When an empty room is half completed in a strong colour, it looks very harsh whereas when the room is finished and the furniture is in place the colour blends into the background. While people have often phoned me halfway through a job, saying they'd just come in from work, seen the colour and it looked awful, no one has ever changed it when the room is complete. If you like a certain colour, choose a strong shade - don't get nervous and opt for a pastel version. Go the whole hog and pick something really dark or really light.
While the cool look, incorporating browns, creams and beiges, is "in" at the moment, I think colour is set to come back - but this time it will be in the form of dramatic splashes of colour on fabrics, pictures and rugs.