Mercury, smallest of the terrestrial planets and closest to the Sun. With it's orbit being so close to the Sun it is a tricky object to spot and it can only be see just after sunset or just before sunrise. As it is eay to mistake Mercury for a star the best way to find it is to check star charts or use a piece of software such as Redshift or Stellarium to find it's location.
Finding Mercury can be made easier if it happens to be near another brighter planet in the sky (see image below) then it is just a matter of locating the brighter planet to find Mercury nearby.
The above image is a reconstruction of the positions of Venus, Mercury and Jupiter as they appeared in the sky on 2 Jan 2009. Mercury can be seen just a few degrees from Jupiter.
Mercury's orbit is inside that of the Earth's so it can also be seen as a silhouette when it transits the Sun.
