Hi. If you have skysafari on your tablet or phone, that can be a good mobile help. Otherwise Stellarium on the pc is a good free program aswell. Stellarium will need to have the Comets loaded into it but in skysafari, they will be there. The big three at the moment are c/2012 K5 Linear. C/2012 f6 Lemmon and c/2011 L4 Panstarrs. Enter that into the search bar of the program/app ( ie C/2012 K5 Linear) the result will show where it is currently located and then fast forward the time to when it rises high enough. Around midnight is good for k5 and f6 and l4 is a predawn low horizon comet currently. I find the best way is to star hop your way, recognising bright stars, constellations and planets and going from there. You can enter the RA and DEC into your goto if you have one. I like to see what patterns the smaller stars make by looking at the programs then finding them first with a wider angle ep. I have not done much visually, I like to image them. I have heard k4 is visible in a 4 " refractor under dark skies.
Here is a link on how to add the comets into Stellarium
http://www.iceinspace.com.au/63-700-0-0-1-0.html
Hope this info helps
