Lots of great answers to your question already so let me offer a different way of looking at your challenge:

If your website traffic is decreasing, then you have to maximize your ability to engage with those that do visit your website to try and increase your conversion rates. 

Here are three things  to consider:

1) Do you have a video on your Home page? Videos can engage visitors and keep them on your site longer which increases the chance they'll interact with you;

2) Do you have a pro-active Call-To-Action? An automated ChatBot that offers to have someone contact them to answer their questions by phone or email is a good example;

3) Are you using retargeting on your website? Retargeting can keep your ads in front of the 96-98% of visitors that don't initially take action and bring many of them back to your site.

While the above suggestions won't help you increase your traffic, hopefully they will help you maximize the benefit from the traffic you are getting.