wireframe cube

Hmm... try a wireframe sphere.

any other suggestions?

Find some tutorials or some book and continue with more advanced lessons.

When you say "draw a wireframe cube", we really don't know what have you already learnt. Can you change your camera? Can you rotate the cube? Could you do something else than a cube if you wanted? Could you render a shaded (not wireframe) cube? Can you do lighting? Texturing? .... .... ....

Have a look at codesampler.com for DX9 tutorials