Who Gives A Shit: How To Buy An Apt in Park Slope?

After five years of renting in Park Slope, I'm finally ready to make the shift to adulthood. That's right folks: I'm going to buy an apartment. I've saved a bunch of money, got my financials in order, and began the process to take out a giant loan that I'll be paying off for the next 30 years of my life. The only thing left is to find the damn place.  

That's the problem. 

See, I'm not really sure where to start. I've gone to a few open houses, but I'm not really sure what I should be looking for or what questions I should be asking. I've been concentrating mainly on Park Slope, but I don't know whether I'll get more bang for my buck if I start moving to the outskirts of the 'hood. And condo or Co-Op? What should I be looking for? 

Clearly I need help. 

Most of the listings I've found have been off Craigslist or Brownstoner. I can't imagine this is the best way to find quality apartments. I'd ideally like to use a realtor, but who should I talk to? I mean, shit - have you walked down the streets of Park Slope? There's another real estate office every two blocks! Can I trust that I can just walk in and talk to whatever agent is waiting for me? What if he/she is terrible? What if another agency has more listings? How do I know?  

I turn to you, FIPS readers. There has to be someone out there who's done this before! Help a guy out here. Have a Real Estate office I should go to? An agent I should see? Anyone or anyplace I should avoid? General tips? Let me hear it!