I think presentation category is the right category to work with.
Congratulation mate Welcome to envato family
I want to give this one for free : http://graphicriver.net/item/space-futuristic-flyer-design/8251506
First of all you have to improve your typography skills and color peeking. Peeking the right color is so tough. But you can do it by following great designers over the world. There is so meany great designers in graphicriver. You can see there typography & Color choosing. You can also follow blogs and tutorials
Learning is the key of your success. Because learning increase your confident. Without confident you can’t achieve anything. 95% of people think that learning about new things boosts your confidence. (National Adult Learning Survey, DfEE, 1998) So Have you learned something new today??