The easiest way you can start a dating site is to use some sort of script. These aren't hard to find, and you can even purchase one if you wish. All you do is install the script on a web server and you are good to go.
Once you have your website live on the internet, you need to find ways that interested people can come to your website. You have to get people that want to sign up to internet dating. You do this through advertising and promotion.
Another way you can begin to get some traffic is through SEO or search engine optimization. With this technique, you sacrifice time for money and slowly get your site ranking for select keyphrases such as, "online dating".
Paid advertising can work well if you are patient and have a good deal of cash to spend. Remember, you may spend a lot getting started, but in the end you will have a good return on investment.
The three main categories of running any kind of online business include research, planning, and executing that plan. Do this and you will be ahead of the game.
Planning is critical. Have you considered customer service? You will no doubt have people asking for help with their profiles, wanting to change pictures, and the list goes on.
If this seems like a daunting task, then start off by selling someone else's product. You will be an affiliate marketer by doing this, and many people start out as affiliate marketers before they make their own product.