Between now and April 20th Mercury should be visible to the naked eye in the evening twilight. Wait about an hour after sunset and you might catch a glimpse of this small world shinning in the evening sky. At the moment it is very low, only about 7 degrees above the horizon. The picture below shows Mercury at 20:15 BST for the 28/3/2017:
Tomorrow you can use the Moon to guide you as Mercury will be 8 degrees to the right of a very thin crescent Moon (NB: the Moon is much larger in this picture than it will be in the sky):
On April 1st the planet will be at its greatest elongation from the Sun, but it will still be low down in the sky. After that its orbital motion will bring it rapidly closer to the Sun and by April 20th it will be at inferior conjunction and no longer visible to us.