The most effective way to advertise on instagram and facebook is an irresistible offer. Dont have any irresistible offer ideas? Go on groupon and you can find proven deals that people are going crazy for.
Then just duplicate that deal to a facebook/ instagram advertisement.
The reason this works so well is because people love deals and if people actively SEARCH on groupon and purchase the deal then if you use the power of Facebook ads to put the deal right in a targeted audiences face that would benefit from the deal you will see crazy results.
Whether you are trying to just build a list, you name it, it works. I use this with all my clients and I have had countless times where we started the ad, spent $100 and they got so much traffic and customers that they had to turn it off. Seriously try it...
Everyone is saying use your pixel, use look alikes but bottom line even though they are effective you can't use it if you don't have data. 90% of you don't have pixel data to work with.
So if you use this method get tons of leads and traffic and then use the data to then create a look alike or retarget (once you have atleast 1000 of the event you want to use) you will kill it on Facebook advertising.