Decide on an overall feel or mood you want the house to have. This will determine your personal style. It can be very helpful to choose a few words to describe how you want the house to feel, i.e. calming and restoring, spohisticated, retro, romantic, kid friendly but cosy, fun and funky, laid back elegance.
Choose the most limiting aspect of the interiors first - there are fewer granite choices than laminates, so choose the granite first then move onto the laminates and flooring and then finally the paint colour. Doing it the other way around can end up being expensive if the paint colour, flooring and laminate choices are made, and being stuck with a hideously expensive laminate, or something that doesn't fit with the rest of the scheme. Sometimes, the most limiting aspect is the existing elements, such as curtains or carpet. Because there are so many paint colours available, this should be one of the last choices made.
Don't guess that you like a colour in store - always take a colour sample home and check that the colour works in the environment. Lighting in the store will be quite different from lighting in different rooms of your home.
Check your chosen colours both during the day, and at night. This is especially important when using metameric paints. Metameric is the organic and inorganic compounds of the colour pigments that "fight" each other, so that in some lights a colour can look completely different than in another light. This gives a wonderful depth and dimension to the paint and environment it's in, but it is important to check.
Do look at colours you are choosing in the largest samples possible. Colourplus have A3 sized paint samples, which are pre-brushed out onto card , so don't be afraid to take these home and put them up in the corners of the room to see how the colour bounces off itself. Tuck the A3 samples behind the sofato see how the colours and textures work together and how the colour works in shadows, and beside the door to see how it works with colours in connecting rooms.
Think of your home as a whole even if you are only doing one room. Make sure there is flow between living spaces by having colours and textures throughout.
Do consider the architectural style of the house, lighting, and properties and fuctions of a room when choosing colours and finishes. A small room does not necessarily feel larger by painting it a light colour, but it will help if it has lots of natural light. There are times when painting a room a rich colour to create a warm ambiance is a better solution for the space.
If you are looking to have more than one floral or stripe in a room, remember the golden rule of proportion - they must not be of the same scale or they will fight each other and create discord rather than harmony. Choose small and large, or medium and oversized to get the balance right.
The rule of proportion is equally important when using strong colours - to get the colour balance right, the proportions of colour must be balanced, and that means not 50:50. One colour must be allowed to dominate and be the focus. In designing there is a classic 60:30:10 equation which equals a winning colour scheme.
Lighting can make the world of difference to each room. It should be one of the last decisions for the room (even if that "room" is outdoors), but it definately shouldn't just be an afterthought.