I have been contemplating some of the decorating considerations that you need to take into account when two people move in together. Whether it be two room mates moving into the same space, or two people romantically linked coming together for greater intimacy, the environment you inhabit will have to reflect the personality of both parties. If one person dominates the space, the other can quickly find themselves feeling like an alien in their own homes.
One of the things about moving in together, is that both people involved already have a certain amount of stuff. If the situation is between room mates, each person will have a room where they can store and enjoy their possessions. In the case of a couple, things are a bit more complicated, with each person having to pick and choose from amongst what they own, as they populate the space.
Another option is to use the move as a chance to completely redecorate. This allows you to create something together, and can be a wonderful bonding experience. It is also easier to re-imagine a spaces decor from scratch than it is to integrate the individual styles of two different personalities.
If one partner or room mate is dominating things a little too much, it can make the space seem cold and unfamiliar to the other. An easy way to combat this is to carve out a corner, or small space in the home, and reserve that as the neglected parties personal place. This can be as elaborate as giving them the garage to fill with their hobbies and models, or as simple as keeping a comfy chair around where they can feel comfortable.
Blending is about more than just space, it is also about the artistic vision of each person, being played out in an environment that you will both have to live in. This incorporates taste, interests, even hobbies, and it is important to be sensitive to each others feelings. If they are a fan of chess for example, you can choose to incorporate a novelty chess set of your choice into the space, as a comprimise between taste and interest.
Color is actually a very powerful and important element of a home atmosphere. When mixed in various patterns, different colors can have relatively dramatic effects on the mood of people within a space. In general brighter colors will be more invigorating, while darker colors will tend to feel calmer and more peaceful. This can be balanced against the personality of either a lethargic, or over active individual.
If you have one person that is calm and another that is manic, blend hot and cold colors together to make both feel comfortable within the space.
In general coming together and creating a home really is about blending what each of you considers to be beautiful, into a joint artistic creation, that you will actually live in. It is a pretty cool adventure, and it can really bring two people together.