I'd say first off that scrap the intro. If you look at popular channels you'll see that very few have the type intros that are very popular amongst small youtubers. Second, I'd have to disagree with
@fattmat here and say that you don't need to invest in banners, logos and thumbnails. Instead, learn how to make them yourself, its a rewarding process which in my opinion should be done by the content creator. I do, however, agree with him that you should invest in your system. Without a decent system you wont be able to play and record games that most people want to watch.
My final bit of advice would be to try and make your videos compelling and engaging. Edit them in such a way that the audience is engrossed in the video and wants to watch to the end, that way, you'll get better retention time, and, with better retention time comes more subscribers and more views.