Travel niche help?

So I run a website that offers day tours in Paris, very well ranked in TripAdvisor (top 20 overall in Paris and top 5 in a couple other categories) but I just lost my biggest customer, they changed their strategy. I am at my wits end trying to get more traffic to the site/conversions. I'm fixing the website itself which will be ready next week. I have my target demographic: single travelers in their late 20s/early 30s and couples in their 40s/50s, mainly from California and New York with obivously high disposable income.

My marketing skills are nil. I've been thinking of affiliate marketing, adwords, facebok but honestly, I do not know where to begin.

If anyone has any direction or advice on any of this it would be GREATLY appreciated.

I used to work with some Travel services...
All were based on Google's traffic and were optimized for keywords like:
Top-10 things to do in UAE for US citizens, TOP-1 attraction in Dubai, etc.

We also wrote a lot of such articles (I guess that you'll find some of ours if you'll search) and posted it in local Outlets (to rank both: the Service and our articles too).

Have you considered getting your website tested? After you've fixed your site, I recommend getting a User Research Platform. It's helpful to get insights from people who are actually using your site and see which area needs more improvement.