Help me improve my eBay Business

I have a company on eBay called screenzies (Search Screenzies on google). We sell mobile phone screen protectors - tempered glass and plastic. Our prices are very cheap but we are not getting many sales. I invested into redoing my eBay store and having a better listing design but people are still not purchasing my items. I am looking for someone who has expert knowledge with online sales, marketing and eBay to help give me some guidance to improve sales. I have around 90 listings but some are duplicates, so around 75 original listings.