A great room to start with is the bedroom because of the simplicity that most sleeping spaces have when it comes to furniture. Most bedroom home interiors have a bed, a few sets of drawers, perhaps a dressing table and a TV. Starting in a small room that most people don't see will allow you to wet your feet and practice designing the room before making purchases. Once you have your bedroom completed you will have the burst of confidence necessary to move on to bigger, more public rooms.
Moving into a new home, or redecorating an old one can be a stressful experience. Work on your layouts and plans one room at a time, utilize color wheels and always make sure to double check your measurements just in case. If you take it room by room and work out your full design before purchasing anything major, you will find it's not so bad having to do your own home interiors.