New to selling ad space. Need some advice.

I would focus on implementing a proper adsense infrastructure.
Inserting the system alone doesn't cut it and optimizing it and properly learning it does.
After that, you'd be ready to take a leap forward to DFP.
Google's next step for the ad space journey. With DFP and unlike adsense, you can control every aspect of the advertising mechanism. This means that you sell the ad spaces yourself and use their mechanism to handle it all for you. Essentially, your own minified adsense network. The beauty is you can then close deals, out of the google system. This requires lots of work. You have to live in ad exchange networks and utilize media companies. The media companies that support DFP usually have the clients looking to advertise in particular ad spaces. A perfect match means big bucks for you. If I owned an eCommerce shop, I'd be willing to go the extra mile to get some juice from your niche traffic. Of course, this assumes you're traffic is always maintained and leveraged. You could boost this entire process by pushing your blog. Your blog could include some youtube videos and such. In the beginning don't focus on advertising. You're too small and need to focus on providing value. Provide value via all your channels and on your site. Push this value to users in various methods. Outbrain could push your blog posts to many places. These blog posts have the youtube videos in them as well so you get two for one in this case. Think of these random methods I'm throwing your way.

The idea here is to create a proper funnel.
A user reads a blog post, watches a video and subscribes for more value.
Don't chase the money and let it chase you. If you work by that understanding within 6 months of solid work you could start to see some small figures generated. Again, keeping the ads minimal and not obnoxious. People get carried away and ruin the user experience.

I can't emphasize value enough.
Value comes through the content and the UI & UX of your site.
Value comes from checking your site load time and making sure it's at incredible speed. (GTmetrix is one simple free tool to start)
Value is learning SEO so that you can understand how all of the organic growth actually works.
Value is not just chasing numbers but creating something and thinking how to make it better.
You've entered a big world where "work from home" dreams are constantly sold. Walk before you run. Focus on getting to 10 page views a month before you think of any revenue.