Implementing your product categories is technically easy if you have taken the time to plan them first. Think for a while about the most useful structure for your customers; particularly what makes it easy for them to find what they want. This is a process that will probably involve looking at your competitors, thinking about logically dividing up your range, as well as a bit of creative thinking.
This recipe will implement a category structure with one level of subcategories but it would be very easy to adapt it to implement a more complex structure or a simpler one with just top-level categories.
Before you get started make sure you have your category structure clearly mapped out on paper or in a text file. Also have in hand some excellent sales copy to describe your categories ready to paste into the appropriate places. VirtueMart can also accommodate category images and although these are optional they will likely enhance the appearance...