It should be roomy for the car to be safe, sheltered. But as most of the owners choose that the garage be attached to the house, it should not interrupt or disturb in any exterior architecture of the house.
It is best to choose a garage door that has the same color as the exterior trim of the house. If you can not do this or not you desire, garage door should be in harmony with the rest of finishes, meaning shade chosen to “match”.
inside , the garage should be as cool, but not wet space. The space inside the garage can be used in your favor, because there can be placed shelves or cabinets. If the garage is small, they can be suspended. The boxes with things you do not need will find their place on the shelves well. But if you have children and a spacious garage, you can make good some of it into a playroom for cold days. You can not do this if it is not well ventilated garage or if there are no smell of tires or exhaust fumes.