10 ways to promote your website

1. Blog on your website with useful relevant topics and giving useful tips or advice

2. Guest blog on other websites with a link back to your own 

3. Join forums to answer related questions with a link to your site or even just your domain email or username to create a link

4. Do public talks on your subject and promote the website that way

5. Include your website details on your business stationery, letterheads, business cards, invoice, statements etc

6. Likewise include your website details in your email signature with a direct link

7. Use company vehicles to promote your website

8. Include the url on all signage

9. Create Social channels to promote your website in LinkedIn, Facebook, Twitter etc

10. Add a Google+ page

You can open a Google Adwords to promote your website for a fee and it is well recommended that you do so.
Likewise you could advertise on Facebook adverts and again it works well, if used properly.
Both these options need careful managing, as they can end up costing a lot of wasted investment. This is where a social media marketer or a digital marketer can add a lot of value.