All of this is meant to be constructive, so I hope you find something useful here, and obviously you'll need to pick and choose what you think will best suit you...
Description...
I advise formatting these for a more professional presentation (I don't mean anything super fancy, just a bit of general clean up will do) - you're selling stationery...some of your customers will be students, parents of students, etc, many others will be business owners like yourself. Just a personal opinion, but I would:
- remove all instances of emoticons
- keep the item description the primary focus (larger font - remember some people will be using phones to view and buy, so I switch to 18 rather than the default 10 or 12 for description text, otherwise most of the content seems fine, comprehensive but succinct, but right now eBay third party advertising and cross promotions mean other seller's ads are taking up more real estate on the listings that your own description)
- put any terms of sale after the the item description
- remove the blue type asking customers to contact you about discounts (primary reason, though I understand exactly why you have it there, no matter how well-intentioned it may be, eBay often views such invitations as trying to deal off-eBay - I had "custom orders welcome" in my listings, got pinged with a policy violation, and there was absolutely no reasoning with eBay, better to just say something like "happy to combine postage and save you money wherever possible" or some such similar phrase that clearly indicates it's for purchases made on eBay).
Honestly....I'd also consider changing the store name. The only time people can really pay cash is when they pick up (and most people would expect to save on postage in that instance), but the vast majority will pay you via PayPal, and may view the offering of a discount for cash from a newer seller as a bit off-putting (i.e. less trustworthy, basically because it's a common tactic of scammers, to get people to pay by other methods like bank deposit).
As everyone else has mentioned, store categories are the best tool you get to cross-promote your own items and make it easy for people to browse a specific section. As a buyer, I use them all the time and have often turned away from a store that has everything in "other", sometimes even when their categories are too broad (eg in a music shop "female vocalists"..... that's not really a thing people look for as an option to refine searches, so if every release they've got is in a category like that, I'm not wading through it... )
Another reason eBay's (not store) categories can be important, I recently received a discount voucher from eBay, but it was only valid for specific categories. There was some stuff I wanted, but heaps of sellers didn't have them listed in the category I needed them to be (I was looking for business supplies, which is one of the cat's that the discount was valid for).
Consider playing around with some different promotions. I definitely feel cdifferent promos will work better for different items. For example, in my categories, buyers often purchase multiple, different items at once, so I have the most success with the "Buy X amount and get Y% off" discount.
Also consider offering express in addition to standard postage, just because I know from experience, stationery is on of those things a lot of people don't look to buy until they already need it (myself included 
).
