Choose an Appropriate Domain Name

Although you are going to attempt to generate income by promoting a dog food related products as an affiliate, the primary focus of your site is going to be on boxer dog training. The next job is to register a domain name that is relevant to the subject matter of the site that you are going to create.
Ideally, this domain name should be one that is directly related to the primary subject matter of your site, although that may be situations where you choose a domain name that is related to the product or service you are promoting.
This is important, because having a domain name that is appropriate or related to the primary subject matter of your site makes it easier for both human visitors and the search engines to understand what your site is about from that domain name.
It also helps when you are promoting your business a little further down the line, so choosing the domain name that is directly related to your topic has plenty of value to your business.
I mentioned that sometimes, you will choose a domain name that is related to a product or service that you are promoting. This is most appropriate if you were going to create your own product as in this case, you would try to give the product a name that is directly related to your subject matter.
Hence in this situation, the topic of your site, product name and the domain name you choose would all logically tie together very neatly.
For example, if you were going to make your own product that is specifically related to boxer dog training, you would choose a name for your product where the appropriate domain name is still available.
If you were going to create 'The Boxer Training Bible' for example, you would check that the same domain name is available before starting the product creation process.
As every domain name on the internet has to be unique (there is, for example, only one Google.com or yahoo.com), if someone else has already grabbed the name, you cannot do so.
Because every domain name is unique, you should try to come up with a list of the least half a dozen viable alternative names before beginning the registration process. By doing so, you ensure that a least one of the names which you are considering registering is still available.
In the current scenario, the primary thrust of the site that you are considering building is to give people information about dog training and in particular, how to train boxer dogs. Consequently, it makes sense to focus on boxer dog training when you are registering your domain name.
In order to register a domain name of your choice, you need to use an online domain name registration organization like The Internet Company. On their website, you simply type in the domain name that you want to register to check for availability.
This is a name that might work for the market in which you are thinking of building a business:

Click on the 'Search' button to check on availability and note that I have left the domain name suffix on the default setting so that I am applying for a '.com' name. Wherever possible, you should always use .com in preference to any other suffix because despite the surfeit of new domain name suffixes over the past few years, the vast majority of net users still think of the World Wide Web as being a '.com place'.

This in turn means that when they vaguely remember a domain name, most people will type their best guess plus .com into their browser window. Consequently, if you have any other suffix rather than owning a .com site, you will lose visitors who are trying to remember the name or URL of your site.
As suggested, because every domain name is unique, you will undoubtedly find that many of the most popular names that immediately pop into your head when you are tried to think of something suitable for your new site will already be taken.
However, in this case, the name that I have selected is still available, so I would go through the process of registering the domain on The Internet Company website:

As part of the domain registration process, you will be offered a choice of how long you want to register the name for. Although you can register for as short a period as only one year, I would recommend that you register your new domain for at least two years. This is because it is generally agreed that Google and the other major search engines accord more credibility to domain names that are registered for more than one year than they do to those that are registered for the shortest possible time.
However, there is a counterargument to this, especially in a situation where you register a domain name that is very specific to one particular product (as many marketers do).
In this case, you have no way of knowing how long the product you are promoting is going to be popular in the market, and it becomes unpopular, no-one will be interested in buying it. It is therefore possible that you could end up with a product-specific domain name with no attractive product that you can realistically promote by using it. Thus, there is a degree of care necessary if you're going to register a domain name that is very product specific.
Remembering however that the main target market for the site that I am creating in this particular example is populated by people who are looking for information pertaining to training boxer dogs and that I am not promoting a specific product in the domain name, this is not a problem.
I would therefore register this particular domain name for a period of at least two years, which is something I would always recommend you should consider. BoxerDogTrainingExpert.com it is then!