What can i do to improve my golden retrievers coat?

buy him another coat?
References :

do u take ur dog to a groomers? u should! TRUST ME!!
References :

When you feed him his food add an egg to it (especially the yolk part) as this will help shine up his coat
References :

shoot, uhm probly buy him another one?
but i kno all dogs shed and i just herd to just keep brushing it it helps it and it also feels good to the dog..try taking it to petco u might have to buy some special medicine
References :

He could have allergies or mites that are making his coat not so hot. A vet could take a look and tell you so that you and your pup will be happy.
References :

What brand are you feeding him?

Give this site a look, a higher quality food would probably make a difference.

http://www.dogfoodanalysis.com/
References :

Wash him once a week.
Spray animal friendly stuff on his fur to make it look all glossy and shiny.
Feed him the pet food you see in the commercials and he'll look like he's a pet star in no time!

What do I know. I don't have a dog. But it could work!
References :

i would take him a bath with regular shampoo but add some vegetable oil and rub it in his coat then wash it out it makes dogs coats shiny and silky
References :
moms a vet…and we tied it on our dogs

Look for a good quality dog food that's for the coat, Premium Edge has a food that's Salmon and is good for the coat, called skin and coat. Taste of the Wild also has a salmon formula that's good for the coat.
References :

You can buy quality of dog food that has ingredients in it to promote healthy coat and skin vitality and it makes their fur shiny. We got ours at Pet Smart or Petco. Walmart may have some too but invest money in a good brand of food, it is well worth it for your dog. Read the packaging and it will tell you what good that food may be made specifically for by what vitamins they add and such. Both our dogs have shiny coats- beagle and a jack russell.
References :

regular grooming and high quality food…you didn't mention what kind of food you feed, but poor nutrition can directly effect the quality of coat.
References :

It sounds like he might have allergies but you should add fish oil in his diet. Not too much because it will give him diarrhea and besides that make him smell bad. If you brush him every day he will not shed that much. I highly recommend the furminator brush. It is pricey but it works wonders. Definitley worth it. Also try spraying tea tree oil on him. That will do wonders to his skin and coat. I think Omaha Vaccine carries all those items. Google them if you are interested.
References :
I'm a dog groomer

take him to the dog groomers..also lil bacon grease could help shine the coat up also rice or some egg mix well in to there food..
References :

Has the dog seen a veterinarian? It could be an underlying skin condition or allergies. Generally speaking, feeding a high quality diet, especially one that contains a decent amount of fish and fish oils (these include Wellness CORE Ocean, Taste of the Wild Pacific Stream, Orijen 6 Fresh Fish, Nature's Variety Rabbit Instinct, Nature's Variety Prairie Salmon and Brown Rice formula, Nature's Logic Duck & Salmon, Natural Balance Sweet Potato & Fish formula, Acana Pacifica, Spots Stew Adult Wild Salmon, Before Grain Salmon, Fromm Four Star salmon a la veg, Fromm Four Star Surf & Turf, GO Natural Wild Salmon & Oatmeal, Blue Buffalo Fish & Sweet Potato, California Natural Herring & Sweet Potato Adult, Techni-Cal Natural Blend Salmon & Potato, Flint River Ranch Premium Fish & Chip Dog Food, Harvest Blend Supreme Fish formula, Merrick Campfire Trout Feast, Premium Edge Skin and Coat Salmon, Potatoes & Vegetables, and Wellness Fish & Sweet Potato), and adding some omega 3 (no omega 6) fish oil tablets or pure salmon oil to the food can help immensely in improving the coat.
References :

Try putting a raw egg on his food 2 or 3 times a week. I did this on recommendation because my Lab had super dry skin. Not only did it fix that problem, but her (white) coat turned super shiny and pretty! I still give her an egg on her food 3 times a week and get many compliments on her soft shiny fur when I take her for walks. And, of course, SHE loves this treat! : ) Something to do with the fat/oil in the egg, i don't know? It works! And it never made her sick, I promise!
References :
personal experience

I have a golden retriever which had a dry dull coat, I consulted our vet who recommended Evening Primrose Oil (capsules from supermarket) after just one month his coat is beautifuly shiney

Forgot to say one 1000mg capsule per day .. Should not be given to dogs suffering from epilepsy