Honestly, making friends is something I've never had any trouble with. I'll just talk to pretty much anyone (in answer to the question in the OP, I tend to start the conversations) I find interesting and just see how it goes from there. It'll sound obvious but really a foolproof way of doing it is to just not give people anything to dislike, and to stay aware of how you're presenting yourself; lots of people can really easily seem hostile without even meaning to, for example.
As for making stronger friendships, now you're getting awkward. I seem really outgoing but I'm actually a very private person and until I let people past that, I don't make strong friends. Which means that I pick very carefully who gets past the private side of me, so I don't have that many really strong friendships. But I'm ok with that because I don't think you're meant to have many!
As for online vs offline friends, I think it's easier online. Mainly because you're already in a place where you share a common interest with everybody (in this case, Pokémon) and also because you can't get judged based on looks and such online. I don't like to admit that this happens offline, but quite honestly, how you look can quite often say a lot about you so I think that people can sometimes be evaluated immediately on the way that they look. I could be wrong there, though. Body language also doesn't apply online so if someone would find you awkward offline, they might not see that online. And then there's also conversation; online you have time to think over what you say before you say it. You never stutter, never speak too quietly or too loudly, or anything like that. Communication on the whole is far easier online than offline so it's easier to make online friends.
Toujours said:
The other day I was at a football game and a girl was standing all by herself watching it. A guy came up to her, introduced himself, managed to keep up a 5-10 minute conversation, gave her his number, invited her to a party, and they ended up hugging goodbye. I was shocked and wondered 'is this how people normally make friends?'
Ngl from my experience, uh, yeah. Although to be fair that was pretty quick.