People tend to feel the effects between 15-30 minutes.  However, some people do fall outside this range and may feel effects faster or slower and it may vary from day to day depending on your fluctuations in body chemistry.  If you let the tincture absorb more under the tongue or in your cheek, you may feel the effects faster since absorbing it mucosally allows it to reach your blood stream faster.  If you swallow the tincture without letting it linger, it may take longer to feel the effects.
The duration, or how long you feel the effects, varies by person and is also dependent on your body chemistry and metabolism.  In general, tinctures last 2-6 hours.