Yeah, art is a problem for most of us developers with no sense of it and ADHD as well. I don't have much advice to give other than to try to use some debug crappy asset till you develop the features you want.
Thankfully, I've overcame that little problem. Art isn't a problem as it once was...sure HUD will be a pain in the rear, but I know enough to make the basic HUD and I can spend hours later trying to perfect it;
1 - (3) Pick a language and SDK and stick with it.
Basically it's Irrlicht or Panda3D, depending on what I'm aiming for; This newest project (lets hope it works out!) will be done in Panda3D; primary reason: it's the only engine I got to step 6 with >.< the only reason why that game was canceled was because I did a very stupid thing and told Panda to do collision detection using a ray-polygon with every polygon that wasn't the character...and that was a few years ago now...