Apart from stating the obvious and listing your domain on sites like www.flippa.com, www.afternic.com and www.sedo.com to name a few. There are other ways to find buyers.
1) Create a Landing Page and do some Seo. If you don’t upload your domain to all the search engines, how do you expect them to list you?
2) As above list to reputable Domain Broker sites.
3) Advertise on all the social media platforms.
4) Find Groups and Pages on Social Media that you can join.
5) Search Google for similar names as your Domain and especially concentrate on the ones that are not on the first page of Google for example.
The companies will appreciate the value of your domain if the keywords match your domain name to help them rank better.
6) Remember to use charm pricing. Rather than list something for £2000, list it instead for £1,999.99 its only one penny less but it looks less and more pleasing to the eye.
7) Search for hashtags that end with your domain name and contact the people behind them.
8) Paid Per Click Advertising tells you the end user needs help being on the first page of Google. Do not approach a company that has a natural listing as they will not see the value of what you are trying to sell them.
9) Try Angel Investors. There are plenty of companies advertising investors waiting for an opportunity to knock.
10) Consider approaching investment companies.
However before you contact anyone do make sure your domain has value, no one wants to be bothered in their busy schedule with inferior domain names.
Go to www.namespro.com to have your domain evaluated or use www.esibot.com although with esibot algorithm it will evaluate your domain on stats rather than a professional opinions from an experienced Domain Brokers.