Perhaps the kitchen is your bete noir? If it is you can do a lot with some new blinds and lampshades. Try some potted plants on the window ledge this can brighten most kitchens. If the paint-work really is past its prime then you need to decide whether you need a whole new paint job or whether you can get away with touching up the doors and base boards. If your bedroom needs a face-lift then try some new bed covers and toning curtains. Add a few cushions to your bed and you immediately have a more luxurious look.
When you first get started on home interior decorating, it is a good idea to have at least some notion of the kind of color scheme you might like. That is not to say that you cant change your mind while you are working out a plan. It is much better to change at this stage than when you already have the paint on the walls.