SubWrite is an app that will make all your note taking needs easier by subcategorising notes and grouping them together in a method effective for you. The way it works is that each note can contain several subnotes that lead to other notes and so on. This is useful if you have a large range of related things you need to keep track of. For instance, you might start with a "To do" list and each item then contains extra details, so maybe the first item in the list is "Get Groceries", you click on that item and you'll then have a list of groceries. How useful!