Yeah, play a lot and get a ton of IP, i mean that's obvious. What gamemode do i play to get the most IP the fastest? I'm currently level 30 and trying to get new champions, its so bad that i still haven't become eligible for ranked queue because i don't have enough champions.
I spam ARAM myself.
I'm pretty sure the IP/time isn't drastically different between modes (although they're not identical), but theres also the occasional generous soul who gets an skin boost which also features a bonus 100ip for the match.
Focusing on something that isn't ip really feels the best though. So focusing on completing missions, or grinding ranked, or focusing on getting mastery X on a champion tends to be pretty effective since it takes your mind off the ip, and then suddenly you finish your other goal and have a few thousand IP that you didn't feel like you grinded for.
I remember , back in the day when I got to 30 first time, I bought IP boosts for like 2 weeks when I knew I was gonna play allot, that's how I got mine in time, now I got like 30k IP and all champs, dunno, if you don't want to spend money, maybe spam ARAM but it will f up your skill if you do it too much ...
either buy champs or just constantly play games daily. a good chunk of that ip comes from first win of the day bonuses. also getting lots of ip takes time too, so be patient.
Smurf?
Mostly people get a lot of IP since they aren't buying champions, even with a 'lot' of IP a few 6300 champions will quickly bring it down to none.
And then theres the people who've already bought everything and have like 100k.
