Marketing professionals regularly ask me how they can improve their online marketing skills, and my response is always, “Online marketing starts and ends with analytics.” The whole premise of online marketing is that you can measure the ROI on everything. No more hand-waiving to your CFO when s/he asks what the return was on a specific campaign – with online marketing you can say EXACTLY what the return was for the spend.The problem is that I find a lot of online marketing professionals are particularly weak in analytics. They know a little about Google Analytics or another tool, but they don’t really dig into the numbers. Well, if you are going to tell your CFO what the return was on your campaigns, you (or someone on your team) needs to be a rocket scientist when it comes to analytics. Everyone wants to jump into all the sexy functional skills like social marketing or email marketing, but if you cannot measure your results, you are missing the point.I also see a lot of marketing professionals cast about looking for new analytical tools. However, when it comes down it to, most of them only use 1% of the capability of Google Analytics, and Google Analytics is free! There is no need to look for something better if you are not really using the tool. Google Analytics is really an amazing tool when you dig into all the advanced goodies like custom variables, event tracking, advanced segments, profiles, custom reports, the API, etc.Learning Google Analytics is mostly a mental challenge. You can set the tool up on any web site in a few minutes so the learning opportunity is right in front of you. However, really squeezing a lot out of the tool takes some tenacity – the product is deep and wide and takes time to learn. One book on the topic that I particularly like is, “Advanced Web Metrics with Google Analytics” by Brian Clifton. The book walks through how to use all the advanced capabilities of Google Analytics in the real world – how you apply the techniques to SEO, paid search, video marketing, etc. Having said that, the most important thing is not which book you read, but that you read everything you can on the topic of analytics.So back to the task of becoming a better online marketing professional. Analytics is so important, and there is so much to it, that you really have to work analytics first and last. Start by learning a ton about Google Analytics by reading as much as you can and applying your knowledge in the real world with some real site. Then go build up your functional customer acquisition and customer engagement skills (paid search, affiliate marketing, SEO, social marketing, email marketing, etc). Then when you have built up your customer acquisition / engagement skills,come back to Google Analytics. Analytics are so important that you need to be reviewing them regularly. Hey online marketing professionals, if you are not a Google Analytics guru, you are not an online marketing professional!