There are a few techy terms associated with website design and analysis of its performance which sound complicated but really aren't. Here's an insight into the more basic:
Bounce rate: The percentage of visitors who land on your website and immediately leave because it doesn't seem relevant. A high bounce (60% or more) is bad as it tells Google that a lot of people are struggling to find your page relevant.
You can improve bounce rate by considering what your customers see when they land on each page; is it a large image that stops them from getting to your main content? Maybe it's a sliding bar which people like less and less as time goes on. Or maybe the content is too vague or doesn't pertain to your header. Think about what your customer's question might be, and answer it.
Behaviour: This is something you can analyse through Google Analytics. This shows the paths most commonly taken through your site, giving an indication as to what your sales funnel looks like, or perhaps indicating that your customers are struggling to find something.
Once you know what your sales funnel looks like, you can own it. Say the common path is Home Page, Blog Page #3, Product Page, Checkout, you could help them with this process by either extracting content from your Blog and placing it on the Home page if it's relevant, or adding links at the bottom of each of those pages to the next step to save your customer having to find the path themselves. Alternatively, if it seems to be more of an adventure than a process, you can identify what your customers are looking for and provide that information earlier on.
Conversion: The act of a web visitor completing an action which is desired via your website, whether it be signing up to a newsletter, submitting a contact form or completing a sale.
Google Paid Advertising: Google is one of the biggest companies in the world and practically owns the internet. Paid advertising has many branches across the Google network, from providing the ability to sponsor certain keywords to show your website listing at the top or on the first page of Google, to showing images of your products to in-market customers, to showing video adverts to customers on YouTube and other participating sites and more.
Organic: The term used to describe the way your page is listed on Google when you haven't paid for it to show up there. Organic traffic is the percentage of people who reach your site through a normal Google search where they haven't clicked on an advert and cost you money in the process. Good SEO results in higher amounts of organic traffic.
SEO: Search Engine Optimisation is the process of ensuring your website is not just relevant, but it is also well-structured and rich with keywords to help Google to understand the content of your site. When creating a new site or making significant changes to an existing one, it is also important to provide a sitemap to Google, to prompt it to scan your website and get your business online sooner rather than later.
There is a lot more terminology which you can learn, or I can teach you, but ultimately you don't need to know this stuff unless you want to. Optimisation and quality website building is my responsibility as the designer, and you needn't concern yourself with it unless you want to.
Take a look at the available Services