The Celestial Observer webpage offers an extremely useful online resource called CalSky which can be customized for your location. Here is the link.The American Meteor Society is a good place to start to learn how to observe both annual showers and the occasional, unexpected fireball.
It often happens that a newly discovered comet will blaze into glory for a few weeks and become an easy and impressive viewing target. But you have to know where and when to look. Gary W. Kronk’s cometography.com is a good place to start. At any time, there are dozens of comets that would be observable in a fairly large telescope. Here’s a site that is updated regullarly. Is there aything out there tonight to observe?It is the rare visitor that gets brighter than 6th magnitude, which is the naked eye limit under ideal skies.