So picture that idea in your mind and really see it, try to make it as clear as you can (hence why simple is good) now hold onto that image and look at your clay. What you want to do here is to try and superimpose that image in your mind onto the lump of clay in your hand. Spend some time just doing this; it is very important to learn this technique because once you are able to do this - even if it is just for some simple pieces - you are training your best tool, your mind.
Okay so now we have the lump of clay before us, we are visualizing the thing we want to make, now what? Well what you are doing is seeing what you are going to need to get rid of the clay from around your potential sculpture. Do you need a small spoon to scoop away the clay, a butter knife to slice it away, a tooth pick to poke in some details or press in some lines? Wait, maybe that lobster pick will get in there! Or the old... what the heck is that anyway? Whatever it is, it might do the trick.
What I am showing you is that all the shapes you need to scoop, slice, hammer, mash and roll are already in most of your homes. Polymer clay is non-toxic, so whatever you use can be washed and used safely later.