By now you understand your baseline metrics like your conversion rate and you have enough traffic to quickly determine what works best you can begin to conduct A/B tests on your landing page.

An A/B test allows you to compare two versions of the same page against one another. Some visitors will see version A and some will see version B. Then you get to see if A works better than B. For more information about A/B testing you can read this article.

I recommend using a service, like Optimizely or Visual WebSite Optimizer that specializes in A/B testing. They make it simple to test variations on ANY of your web properties.

For your first A/B tests you should simply try testing two very different headlines that you created in a previous milestone. You should also try changing big things like the hero image or sub-headlines. Changing the detailed copy will rarely result in large gains as most people won't take the time to read all of it closely. They just want to know it's there. :)

These A/B testing tools will help you record the conversion rate for each variation so that you can pick a winner. I also recommend keeping notes on your experiments so that you can look back to see what things didn't work and avoid repeating tests in the future. Having this record will also help you create new landing pages because you'll know what combination of things has worked best in the past.