These are the steps that I like to follow to create, review and implement a new IA into a website.
Review the business goals and current IA
It's always important to start but understanding what the business is trying to achieve. Whether you want to increase sign ups to a mailing list, sell more of a certain product or build a community - this will have an impact on how you structure the content.
Next, having a good grasp on the current structure and where it may be falling down is important as that's what you will be trying to fix. This is where analytics is helpful, by using tools such as Google Analytics we can see the most popular user journeys, sections of the site that may be going unused and potential journeys causing confusion.
With this information in hand it's a good time to talk to the users.
As I said earlier 'good IA helps us create clear journeys to get our users to the content they need'. Without understanding what our users need and where they are currently finding frustration it's much harder to design a good IA. Thankfully there are lots of ways to find this information. Some of the methods we have available are:
1-2-1 Interviews - these give you time to better understand your users' goals, needs, pain points
Card sorting - These exercises involve working with users to better understand how they view your content and the categories that make sense to them
Surveys - An easy way to get less personal feedback than interviews but on a much bigger scale
Analytics - As mentioned earlier it's always a good idea to review site analytics and get a picture of what's currently working and what isn't
These are a few of the methods available but the most important thing to remember is; however you go about it, try and gain as much user feedback as possible.
Now you have a better understanding of the business goals and what the users of the site need, it's time to join these elements up. This begins by categorising the content. This is where the Card Sort exercises really become helpful, using the feedback gained from them is a great starting point.
You may have levels of categories, that's fine - sites with lots of content will need a hierarchy of information, think boxes inside of boxes.
These categories are not only going to help you organise the individual pieces of content on the site but most if not all of the 'top level' categories will become the navigation.