Use UTM parameters. There’s a great template here:
Here’s a goal you can set up in Google Analytics for Unbounce landing pages:
This tracks all conversions made on your landing pages. By using UTM parameters, you can see which campaigns and on which channel conversions were made. You may test if the UTM conversions using real-time analytics. The next day, you’ll be able to see if the campaign URL parameters tracked that specific campaign on that specific channel:
As you can see above, it shows our email campaign for our NY event had two conversions. These were from the test I was performing on the landing page using the unique URL parameters I created (URL campaign builder). Make sure you test this and keep the naming conventions consistent in order to track and measure the effectiveness of your various marketing campaigns.