There are many ways to remedy this problem. The easiest way is to sell them. When you realize you're getting money in return for these items, you're more likely to follow through in letting go. Simply ask yourself, do I want to let this take up space in my closet another year or use this money to buy something new that I'll wear several times this year?
You're bound to let go, especially after the sale occurs, since you won't have a choice by then.
If your issue is wanting to let go of something but you simply can't afford to update your closet or you can't find anything to replace it, re-do it! This is definitely for someone who is creative and has the time to do so. I remember having this knit layering cardigan that was cute when I bought it but I ended up hating it later on. So instead of buying another sweater, I shortened it and sewed the opening pieces together to create a cropped sweater that I loved! You're not going to want to re-do everything in your closet but if you have an idea for something, it can't hurt to try since you never wear this item.
A more rewarding choice is to give these items to people who don't have the luxury of choosing what to wear because they simply don't have clothes. You can drop your items off to the Salvation Army or there are some places where you can have the items picked up from your house, if that's more convenient for you. Giving to those in need is definitely the best choice but it may be hard to do this as well.
It is difficult to let go of the things you never wear. It can be because of the quality, it's beautiful design, uniqueness or ironically, because you haven't worn it. But if you do absolutely nothing with it, what value is it actually giving you? Nothing. So do something with it or find a way to let it go. You should purchase items because you will wear them, not to look at them. That's what fashion museums are for.