Start by talking to your vet. But I will share what I've learned from over 30 years of caring for dogs, and observing first-hand the long-term effects of one diet over another.
A lot of people assume that feeding dogs more of a "human" diet is better for them, or assume that, since it would be really bad for people to eat dog food, food made for dogs must not be very good for dogs, either. Not true. Dogs have different dietary needs than humans, so you're not doing the dog any favors giving him/her a human diet.
The best way to evaluate the quality of the food is to look at the results you see in other dogs that have been given the food. If the food has a good track record of keeping dogs healthy, strong, and living long lives, that trumps all the politics and pop theories you hear floating around everywhere.
This is why your vet would be a good person to talk to. He/she has seen hundreds, perhaps thousands of dogs, and knows what diets give the best results. Most people who make their own dog food don't really know what the best balance of nutrients their dog needs; they just guess, based on what they know about human nutrition, with some minor considerations for the fact that dogs are mostly carnivorous. People are publishing their ideas of what makes good homemade dog food all over the internet, and I have seen some real doozies.
My vet refuses to endorse a particular brand, but one thing she does stress is to feed a food that contains a high amount of QUALITY (i.e, easily digestible) protein. If the main source of protein is from corn, that is not easy for a dogs digestive system to process, and makes the dogs kidneys work overtime to get the job done. It's better to feed foods with at least one of the main sources of protein coming from MEAT. Also avoid sources like beef tallow and other fillers.
There are several foods out there that meet these requirements. Science Diet is one of them.