In Google Analytics Reports there are many ways to find out where a visitor/conversion has come from.
1) Conversions > Goals > Overview > Source/Medium
Here Source/Medium represents your Blog-1/Referral conversions. You can check each goal or conversion individually using the dropdown menu at the top.
2) Acquisition > All Traffic > Referrals
You will be able to see all the referrals in this report in a table listed, and you can also select the goal-conversion you wish to track
This is a great way to track your visitors/referrals, you can be more specific as to from where does the visitor visited your website, what link the visitor clicked on and from what page. Mage sure to use the parameters wisely and use the name of your BLOGs as the utm_source to keep it tidy. Note: Of course, the only condition here is that you have to have access to all the referral blogs to edit the links.
Here is the link to get you started, there are plenty of tutorials online.
You can also follow this tutorial to create advance segments for measuring your referral traffic coming from specific domains/blogs. Then use this segment across all your GA reports and goal/conversion reports to compare the referrals campaign impact vs all the website traffic or other segments.
Please note that the tutorial will walk you through how to create an advance segment with social media channels, apply the same procedure with your domains/blogs you wish to track.
Custom Dimensions and metrics
Adwords campaigns allow you to setup custom URL parameters. In Google analytics, as far as I know, you should be using the standard implementation using "Custom Campaigns" if you have the access to edit the links.