I would add some wild caught salmon oil to the diet (You can get it on Amazon). works wonders for the dog and the coat. Remember that old coat needs to grow out. Also try a grooming stone to get rid of the fuzzies without pulling long coat.Look at Youtube for hints on using the stone.
If you feed a kibble you might try a baked rather than extruded kibble it has more nutrition in it.
I have to admit I am a raw food person but my dog has glowing coat and great muscle. No bad breath, that is an indication of either dental or gut distress. I use Knowbetterintheraw.com
It is actually easier and cheaper than you might think. I buy chicken breast, thighs or pork loins when on sale always less than $2.00 a pound and my cost is 0.67 a day for my 10 pound mini. No harder to make than a cake.