The planet Mercury is pretty elusive for much of the year.
So the opportunity window to see it, while a small one, still gives you
the chance to check it out under favourable fall skies.
October will give you the best window of opportunity to get a look at the planet.
Ideally, you want a telescope that has at least 75mm of aperture to observe.
Early in the month, you can see it towards the southeast horizon in the evening.
However, towards the latter part of October, (around the 22nd) an even better view can be had in
the pre-dawn skies.
Again, look towards the Southeastern Horizon, about 90 minutes before Sunrise.
And, just above and to the right of Mercury, you will also see the crescent Moon.
When you observe Mercury through your telescope, it will look like a small semi-circle,
or half circle.
That's how you can be sure you are seeing it.
Consult your favorite App or Skychart/Planisphere to determine specific locations.
PS If you are interested in photographing the planets, including Mercury,then I highly recommend this
DVD by British imaging expert Damian Peach. http://khanscope.com/bookDetails.cfm?productID=5687.
It's brand new, and chock full of specific tips and secrets of nightsky imaging successfully!