1. Set camera to "macro."
2. If your camera has it, set it to "aperture prioriry."
3. Use the timer instead of directly pressing the shutter.
4. Use a tripod.
5. Have lots of light. (And make sure your camera is on auto-balance, or select the appropriate setting to match the lighting you use, i.e. fluorescent, incandescent, daylight, etc.)
And I have one more to add:
6. Don't photograph your model on your grandmother's paisley sofa. Plain backgrounds are always better!
HTH, and good luck! (The sofa thing sounds ludicrous, but I have seen a bunch of people do that!)