I agree with both of the above. And get Profili or a simular program. I am now using my own designed airfoil in some combat planes, and I used Profili to do it.

That said, why do you want to create your own airfoil? Programs like Profili come with piles of airfoil templates, and chances are you can find one that already does what you want.

I've also been designing and modifying others designs for a bit. Almost all the good designs have been based loosely on something else that came before it.

What are you trying to design, and when you say your first design didn't work, what exactly did it do? Though these kinds of things really aren't "beginner" questions, it's rare for someone to design their own trainer, and I would recommend against it.