My shop website is up and running. Now how do I get companies to want to advertise on it and how can I make additional cash with it?

Hi,
Some of the search engines still have partner programs that will supply the ads and pay for click-thru. Google just changed there policy.
Also, if you provide compelling content, then you could put a PayPal graphic there. Lots of sites that provide free membership, information, etc. on open source topics use the "Donate" version of that service. You of course need to open an account.
Peace,
Clarke

If you have a professional type website and have good site traffic, there are many ways to make money online. To your above question what ways can make money, I am suggesting below ideas for that.
1) Sell spaces for direct advertising.
2) Place Google Adsense
3) Use Affiliate products to sale