Before you even consider getting rid of the article or accessory in question, think about the reasons why you would like to remove this item from your wardrobe. Is it an unflattering cut? Is the item to large or small? Does it not fit into your lolita aesthetic? Are you finding it difficult to coordinate?
If there is a chance to remedy the issue, there may be no need to sell the item! You wouldn't want to rid yourself of something you love if there is a way to fix the issue. If there isn't, let's move forward.
Take or Keep Lots of Photos
Find or take photos of the piece! I always seem to have photos of the items, but few of the coordinates. Before I wash and prepare the item in question for sale, I take a few pictures of myself in a lolita coordinate with it. This is especially true if the piece means something to me! If I start to feel nostalgic, I can take out my phone and bring up the memories with ease. It works well for me!