There are lots of accessories to the fly fishing and fly tying. And more are coming. Of course you have to have rod, reel, line, and flies, but...
You have to have a net to get the fish out of the water. A good pair of waders to get to the fish. If you don't want to keep the fish you need something to help you loosen the hook. You need more leader material. You need something to help the floating flies to float, and so on. Hundreds of small things that you don't know you needed until you got it, like.
The best fishing shops have all you need, so get in touch with a good one.
Here are a few items you will need if you havn't already got them: