Now that you have the knowledge about what a dog walker does and you have chosen a business name, it is time to write down exactly what you will offer and what you will charge.
Get out a piece of paper and start writing. What do you want to offer? Do you want to start out with just single dog walking? Will you offer pack walking? Will you offer pooper scooper? Will you offer puppy care? Will you be administering meds? The more diverse you are, the more money you will make and the larger you will grow.
Now that you have written down what you are going to offer, it is time to determine what you will charge.
In my opinion, it is best to charge for your time. Have time slots set up with a rate for each. For example, a 15 minute visit is $15; a 30 minute visit is $18 and so on. This is for as many dogs they have in a single household. I don't think it is wise to charge extra fees for more than 1 dog (such as $1 per additional dog). It turns out being a turnoff for your client when you start to add on more and more fees. If your client has more than 2 dogs, they would end up purchasing a longer time slot since you would not be able to get the job done as quickly.
Many dog walkers will charge a small fee for administering meds. This is fine and recommended. A nice up sell is to add on Pooper Scooping. Cleaning up what the dog does while you are there is included if asked. However, you can offer to clean the remaining yard for another small fee. Basically, what is included in your visit is walking the dog, refreshing the water and cleaning up after the dog. Anything else can be an upsell.