Hi all, I don't know if this was mentioned in the thread but I recommend you all to read Marie Kondo's books on decluttering.
She's helped many with this issue and her approach is marvelous. You can find most of the info for free online, but the books aren't that pricey (and every library probably has them). One of them is an explanation on the ideas behind hoarding and clutter, the other book gives diagrams on how to store everything, from sqaure folded, upright tshirt to pens.