Hi Datesand,
So I have a couple of thoughts here:
1. Are you promoting all of your products equally at the moment?
If that's the case, then why are some products performing better than others? Could it be because your market is responding more positively to those particular products?
If this is the case, then that may mean your market is telling you that they're not really interested in those products.
2. If you're not promoting your products equally, why is that? Have you identified, through market research that some of your products would be more popular than others and so you're currently pushing those products more?
If that's the case, look for opportunities to cross and up-sell products that are related or relevant. Even on your website, you can do like Amazon:
"People who bought this also bought this"
or
"Related products"
etc.
3. Where is your most popular sales channel? Is it online through your website? Offline at your store/location?
If it's online, you can track where people are visiting your site and where they spend the most time. You can use this valuable data to map out the flow in which your visitors take and how they end up at the purchase page on your site.
It may be that they find you through Search Engines? Maybe some of your products are just ranking better on Google than other products and so they get more exposure?
Maybe people are finding your website online through social media, your posts or through Ads and they just take interest in a particular product or promotion. Either way, this is something you need to monitor!
If it's offline, then what are your salespeople saying to your potential customers? Is there a product they get asked about the most by people visiting your store?
Bottom line is, you need to respond to your market needs and give them what they want as well as try to find opportunities to bolt on your related or less popular products to increase your overall revenue.
I hope that helps!
Andrew