You may think it is difficult but actually, it is very simple. Yes, if you want to know how to do gap analysis then all you need is just a good understanding of your current business situation and the goals you want to achieve. In a nutshell, you need to define where you want to go in a concrete way and then determine where you are now.
Let's do a gap analysis example for a blog. Let's say you want to have 1000 subscribers and now you only have 100 subscribers. Then the 900 subscribers is your gap. Then you need to analyze why you are not in your goal. Why is there a gap?
When you know the answer why there is a gap, then you can also think how to close this gap and make your goals a success. That is gap analysis. You can learn about gap analysis in this article so follow the link and read it.