I currently have 64 platinum trophies, working on 65. Bow before my digital prowess that-actually-means-nothing-in-real-life! Mua ha ha! And that's not counting the few games that I have 100% on, but they just don't have a platinum.
Anyway, as you can see, I do like going after my platinum trophies. But only if they're doable--which usually translates into NO MULTIPLAYER TROPHIES! Lord, I hate those ones. "Play a match in this mode" or "Reach level 10" ones are fine. But when you want me to get to the top of a leader board? Or get a kill in a nearly impossible way? Or just kill an obscene amount of people? Or earn a reward for doing something that requires the planets to be in perfect sync for it to happen? Screw you, developers.
I have done a few multiplayer trophies. Got the platinum for Medal of Honor, which required getting all seven kill streaks, which meant you could not die the entire time, because then it resets, and you had to get an obscene amount of kills to trigger the last one. That's probably the one that I got the most excited about. Also got Resistance 2's platinum, which meant I had to kill 10,000 players in ranked matches. Never. Again.
But as a general rule, I tend to stay away from multiplayer trophies, and it bugs me that Call of Duty is slowly slipping them in, because I used to be able to get the platinum on those games easy.
As for guides, I will look up a trophy guide and make notes of what to look for. It actually kind of bothers me when a game DOESN'T have a guide, because that usually means that there are a few trophies that people are stuck on, and finding the answer on how to get it can turn out to be a hassle.
I wasn't always like this. I used to just play the game, and if a trophy popped, okay. But then some friends at work started teasing me, saying I would never catch up to them in the trophy race. It was all in good fun, but they planted the seed. And so I started. They were at levels 15 and 18 (I think) while I was still down at like, level 3. And I started climbing. It took a few years, but I eventually passed one, and then when I finally passed the other, they both just kind of shrugged and said, "Yeah, I'm retired from the trophy race." I'm still a bit disappointed in that, because I used to love chasing trophies with both of them, seeing who could get one first. Now though, one only plays Destiny, and the other only plays on PC.