What does "user experience" mean to you?
Are you the shop owner? Is this a particular shop or a general e-commerce template for unknown shops?
What are the shop's goals? Is it traffic? actual visitors? buyers? returning buyers? unique buyers?
Will the visitors already know what they want? Or will they be browsers (window-shoppers)?
Where will the visitors be physically when visiting your site?
What devices will they be using?
Is their time on the site expected to be long or short per visit?
Are they expected to create accounts and visit regularly/daily?
Will they all speak one language? What age group are they? Which sex are they?
What would your intended group expect when they first land on any page on your site (since people arriving via SERPs may not land on your main page)?
Do the visitors expect a straight-forward finding/comparing/purchasing experience, or do they want to be entertained?
Do you know the competition? Is there competition?
Are the competition's visitors possibly your visitors? Are you aiming to take the competition's visitors or create a new market by being a different niche?
What are the competition's strengths and weaknesses (on their web sites) according to the market, according to the buyers, according to the shoppers-who-are-not-buyers?
These are some of the first things that come to my head when I see a question about user experience.
If you already know a lot of these answers, and post them, then we can probably give you some pointers. I'll note I am not any kind of e-commerce/usability expert, but it's an interest of mine and I read a lot about the topic.
Does anyone need to navigate? If so, then yes.
You have at least two: site navigation (home, contact, about, shipping rates, disclaimers, proclaimers, Don King) and
product navigation (possibly more than one of these). If you only have a few products, you may not need any product navigation, like John's phone. The site navigation includes "Store", a single page of products.
Also how large it is, how fine-grained it is, and whether navigation consists of links, ajaxy-foreverScrolls, a search box or large categories. How deep navigation goes depends on how much refinement users think they need to get the item they are looking for. How long they will continue diving into deep navigation depends on how useful it was put together: if there are too many possible categories with too many sub categories with still more possible subcategories, the user will not feel they are making progress and will abandon it.
Think laptop shopping where users may have a list of demands and are trying to find a laptop who meets all of them.
Think users looking for hotel rooms based on more than just location, price and number of occupants.
Checkbox categorie elimination works well in cases like these, or having category navigation in addition to regular link navigation. Think [laptopshop.nl (left sidebar) and [url=http://booking.com]Booking.com](http://www.laptopshop.nl) (left sidebar called "Filter By", after adding a destination and getting search results page).
The more results that can come up in a search, the more filters you may need to add. Very few results or very few products don't need much complication.
Keywords typed into search should bring up useful things. Typing "foo" into a search of a furniture site should ideally not bring up footstools, but "foot" probably should, and "stool" should bring up both barstools and footstools, even if your site and your manufacturers call them "ottomans". This means simple word-matching is less useful than context-modified word relations. Your search should also be able to recognise the difference between a regular word and a brand name. If you have an unfortunately common word that is also a brand name, allow people to choose one or the other for results, or show results in two separate chunks. If you have a grocery-and-goods site, a search for a brand name like "Kleenex" might mean the user only wants that brand, or is looking for any nose tissues.