A dog getting fleas, or rather fleas getting a dog, is a very common occurrence.  There are things you can do to guard against it such as keeping a clean living environment, a well kept garden and generally keeping your pet in good health, but still most dogs will get fleas at some point in their life.

If your dog does have fleas then there are plenty of dog flea treatments available, some better than others of course.  It is very important to deal with the environment the dog lives in to get rid of fleas entirely however, at least carpets, their bedding and the garden.  If you do not do this then even if you kill all the fleas on your dog they will quickly return (well, not those ones exactly, but their offspring) because fleas grow on carpets, furniture, in the garden, anywhere but the dog itself.  Once the dog is free of fleas, therefore, if their environment has not also been treated then new fleas will simply attach themselves again and you will have the same problem.

One of the simplest, most effective and the safest dog flea treatment, is the flea comb.  The flea comb has special little teeth that take hold of the fleas and drag them from the fur coat.  At that point all you have to do is dunk the comb in a bowl of soapy water and the fleas will be killed.  Alternatively, you can bring the soapy water to your dog in the form of flea shampoos.  Or a normal shampoo will also work, anything that produces a lather will, and with the addition of essential oils such as neem oil it will repel the fleas from coming back.

In fact flea repellent, such as Flea Away, is a good dog flea treatment, both if you think there is a danger of your dog being about to contract fleas, and if it already has them.  Flea repellents are not as strong as certain other methods, and that is a good thing because harsh chemicals can sometimes do more damage than the fleas themselves.

If your dog is having a lot of trouble from a big flea infestation, however, then it might be best to take the chemical route as this is the most effective and fast acting.  Before resorting to this, however, you could try treating the flea bites with special oil, diluted with water and applied to the worst affected area.  This may soothe the skin enough that you can take less aggressive measures in tackling the flea infestation.
For the best advice on dog flea treatment, contact a professional pest controller or talk to your vet, either of whom will be able to suggest the best way to deal with this menace in your particular situation.