Try to make the time you do have together more exciting for your dog on both a physical and mental level. Things such as going for walks, car rides, playing with toys, or teaching them new tricks. Even though you might not have much time, making the most of that time will make a big difference. You can also look into taking them to doggie daycare, day boarding, having a pet sitter drop by, or even a trusted neighbor, friend, or family member who can drop in and give them some attention.