I see many questions asked regarding the shedding process of corgis. First and foremost I must say that corgis do shed copious amounts. It is part of owning this enchanted breed and something that one will have to accept. I will be happy to share some tips to manage the shedding a bit which may be helpful.
Feed a good quality food. Generally I recommend a food that does not contain corn in the first five ingredients. There is no "best" food. There are many good foods. A good diet is the basis for good health.
Fish oil in a dogs food is also beneficial in making sure they have plenty of omega oils.
Groom regularly. General brushing does help evenly distribute the natural oils in the coat. This also removes loose hair. Frequent grooming will help remove other debris that may be lurking in the dense area of your dogs coat. The hands on sessions will also make you aware of any new lumps, bumps or any changes your dogs body may have.
Use proper grooming tools. I love my greyhound comb. Has wider tines on one end and narrower on the other. I usually work in sections, push the coat against it growth pattern and comb. This allows you to get deep down to the skin. Make sure to be gentle. I like a rake when they are blowing coat. This is a small t-handle tool with short tines on it. Short, brisk strokes does well to remove lots of hair. I like using a soft slicker on the britches after combing them out. Makes them look fabulous!
Furminator. This tool is also great for getting out dead coat. Do be aware that is also does seem to pull out viable coat as well. Some people love thinning out the coat, others like their full coat.
Bathing with warm water helps loosen the dead and dying coat. If your dog is tolerant of a blow dryer this is another great way to get rid of unwanted hair. Do not use a human hair dryer unless it blows cool. May find it best to do this outside as the hair flies everywhere!
Shaving. This does not alter the amount of hair the dog sheds but makes the "fallout" much shorter. I do not choose to shave my dogs nor do I recommend it. Shaving the coat can cause great irritation to the skin. Shaving the coat takes the dogs natural insulation away which protects it from the elements. Also opens the skin to bug bites and irritants when coming in contact with plants, branches and brush. Some dogs do not grow back very well and loose the nice coat they had prior to the shave.
Shed stop supplements are generally little more than omega oils. Truly a waste of money. Quality food and fish oil (salmon oil is best) will give your dog the extra boost he needs to have a nice coat.
Lastly keep in mind that if you wish to own a corgi you will have a dog that sheds. This is a natural progression in the growth of a healthy coat. Do your grooming and vacuum/sweep regularly. Keep a lint roller on hand. Covers for the furniture and car seats will also help keep the hair to a minimum. Happy grooming!