As Wikipedia tells, conversion optimization or conversion rate optimization (CRO) is a system for increasing the percentage of visitors to a website that convert into customers, or more generally, take any desired action on a web page. It is commonly referred to as CRO. Conversion Optimization is a structured and systematic approach to improving the performance of your website. It’s data based on analytics and user feedback, defined with unique goals and needs of your site and finally it’s conversion of existing traffic, its greater part.
You can accomplish the full set of activities on your own if you’re dealing with analytics at least at the primary level. Find narrow places in your sales funnel (you can analyze it in a tool you use to get data from your site, GA as an example) and improve it launching A/B/N tests. There are many solutions helping marketers not only to edit web pages on their own but also analyze your traffic to know its quality and so on and so forth. Some of the tools for your needs: Google Analytics, Kissmetrics, Mixpanel, Maxymizely, and others. A few words about each of them:
Google Analytics (www.analytics.google.com) is a freemium web analytics service offered by Google that tracks and reports website traffic.
small, bootstrapped, start-up, or you're a part of a larger organization
KISSmetrics (www.kissmetrics.com ) is a very easy to use, insightful web analytics package that sets your sights on metrics that matter (e.g., your bottom line).
Mixpanel (www.mixpanel.com) is the advanced analytics platform for mobile & web. Instead of measuring page views, it helps you analyze the actions people take in your application or website. An action can be anything - someone uploading a picture, playing a video, or sharing a post, for example.
Maxymizely (www.maxymizely.com) is an advanced analytics, A/B and multivariate testing service. With Maxymizely.com, you can easily experiment with texts, colors, and locations of your CTA and find out which ones convert the most visitors. Also, the service provides crash analytics and traffic analysis to find out if your traffic is quality or not.