I find Twitter is an invaluable resource for at least finding agents and getting some idea of what they want. Hashtags such as #MSWL (manuscript wish list, web homed at http://www.manuscriptwishlist.com) can be helpful, as can various “pitching events” such as #Pitchwars, #SFFPIT, #DVPit, #PitMad and so on. It’s not hard to figure out how to use, and you can always ask here. But it’s worth it because you never know what you might find. I managed to get a free edit for my opening 3,000 words from Jeni Chappelle from there.
The writing community on Twitter is really good and seems to have developed a reputation for itself as kinder, nicer, and altogether more helpful than just about everyone else on that platform.
Of course I say all this – yet no agent! 😉