Hi, I sell on Ebay and it really is easy. The site takes you through step by step. You will need a digital camera so that you can include pictures of your items. Always be honest about their condition. Be realistic as to the cost of post and packing. Get the new post office leaflet re sizing and weight. Its handy to be able to weight your things so you can put the postage cost on your item, so get a good pair of kitchen scales. Be aware that it costs to list items, plus more when you sell (on a sliding scale). If you accept Paypal in payments (very convenient) it will also cost you, again on a sliding scale according to how much things sell for. All in all, its good fun. Ebay often have special 'cheaper' listing days, so it might be worth waiting for one of those and trying out a few items. Searfch for similar items on ebay to see how many bids they are getting, and check other people's postage costs. Some are really trying it on. I would never bid on anything which had to my mind, high costs. Very good luck. I am having a sort out too, and am going to list some large size clothing which is all unworn.
Let us know how you get on.