Sketch the garage exterior and home exterior. Decide if you want to change the exterior materials, such as brick or siding on the garage. Plan to match the home siding or brick, if both structures face the front curb.
Decide if doors or windows of the garage will need changing. Plan to buy high-quality wood garage doors that will match a home's new front door, for example. Buy larger windows for the side of the garage to add more natural light.
Make all needed repairs. Check out the roof for leaks and guttering issues. Install new flashing and asphalt shingles, for example. Repair concrete gaps or cracks on the driveway leading into the garage.
Install new siding, brick or stone veeneer. Cover the sides of the garage with new tongue-and-groove wood and add stacked stone to the garage front, for example. Install any new materials to the home during the garage exterior remodel, so that stacked stone will all come from the same lot. Keep in mind that it's difficult to match any type of stone or brick from two different batches coming from the retailer.
Paint all overhangs, guttering and trim. Caulk these areas well before finishing up the final coat of paint. Use colors that match the trim around windows and overhangs of the house, so the garage does not look like an afterthought. Create a garage remodel that blends with the house materials in a seamless fashion, so the new garage makeover looks original to house construction. Don't paint the garage with fresh paint if it's going to make the house look faded. Paint just the overhangs, guttering and shutters of the house, as one option, to make sure the two structures look equally updated.