Before getting involved in development work, spend some time considering carefully why you want a website and what you hope to achieve. Ask what your website is going to offer that is not already available on the web. Sit down with a wet towel over your head and be brutally honest!
A process such as this helps to clarify a number of basic parameters for your new website. What should it look like? Who am I trying to encourage to use it? What will my target audience expect or hope to find when they reach the home page? What will they be looking for? How will they find the particular information or content that they want? Do I intend to sell anything on the site? How will I take money from customers? How should all my content be structured? What navigation aids does the site require? The technical answers to such questions are not necessarily required at an early stage, but the basic requirements need to be identified as early as possible.
Domain names must be unique and most web hosting companies offer a facility for checking whether your preferred domain name is available. If the proposed name is already in use, similar alternatives may be offered. Consider also whether you need to reserve other similar domain names to protect your own brand. If you settle for "mydomain.com" do you also need to reserve "mydomain.co.uk", "mydomain.org" etc? All these domains can be set up to point to your single home page, so whichever one a user types will direct them to your site. However, there will be a limit to how may domain names you want to pay for! Hosting companies like to offer all the other obvious possibilities because they are keen to take more of your money, but in practice it may not be necessary to use more than one domain. If you intend to be a large business and don't want anyone mimicking your well-known brand then multiple domain names become more important, but for an amateur photographer seeking to showcase good images it is probably not worthwhile.