That "wall" you're describing for me is almost always (and is in this case, too,) just getting started. The scope of things that I want to do is daunting, and the knowledge that I have of the topic at hand is very limited.
Update: I now have a 7 page "Design Document," which is basically just a list of shit I want to do and how I want to do it. Why is this in the sad thread? Seeing it all laid out like this is making me panic. I'm worried that a) I missed something, b) I'm not good enough to get it done, and c) it's utterly unrealistic to expect that someone like me will be able to accomplish this.
Start small and iterate from there. Go for the minimum viable product, then remake it with refinements.
As an example, if you wanted to make a roguelike:
First iteration is literally a blank screen. You now know how to set up your canvas for display.
Second iteration, you get an '@' moving around on said blank screen. Congratulations, you've learned to register keyboard input and refresh your display.
Third iteration, you make sure that '@' doesn't move offscreen. You now have a level.
Fourth iteration, add a bit of HUD to display HP, name and whatever else.
Then you add a static enemy.
Which you then get to attack when the character gets next to it
So you give the character the ability to strike first... etc
Rewrite your first iterations completely to get as familiar with the basics as possible. Only reuse what needs little to no modification to work in the new context.
That should get you started.
Just... Try not to punch your computer ^^