If you want one, simple technique -- put ingredients away as you use them.
When you start the recipe, take out all of the necessary ingredients, and put them on your counter (or somewhere nearby, if your kitchen is as tiny as the one in my first apartment). This gives you a chance to make sure that you're not missing anything critical.
As you use them, put them away ... this helps you keep track of what's already gone into the recipe, so you don't end up with twice as much salt (or none at all).
I find it's most useful with baking (eg, when you'd have a large container of flour or baking powder that you only need a portion of vs. other cooking where you'd just pull out those three carrots or two onions you needed from the beginning). It's also really useful when you have more than one person in the kitchen helping to cook a single dish (the most typical reason an ingredient gets doubled)
I actually don't like chopping everything in advance, as this means that I have to have place to put all of my prepared items (which means more bowls and dishes to clean afterwards). I do make the exception for stir-fry, but I use a few plates and keep things that cook in a similar time together on the same plate; I won't dump in the whole plate at the same time, but if a carrot ends up getting hidden under the stems of the bok choy, it's not as big a deal as if it went in with the greens of the bok choy.
My only other recommendation is in cutting board selection -- I really don't like the heavy, thick butcher block ones, because they're difficult to carry one handed. With a lighter board, I can pick the whole thing up, then use the back of my knife to push things into the pan, or into the trash as appropriate.
... and I guess one more recommendation, but this one's actually from America's Test Kitchen (I think it was in their Quick Tips book) -- when you're peeling carrots, potatoes or whatever ... put down a sheet of newspaper first, then after you're done, you can just fold it in on itself, and compost or trash as appropriate for your area.