Port forwarding seems to work decently if you are not able to hardwire your connection.
Try to play Free-For-All or Hunted Free-For-All as those 2 game modes seem to be the least laggy. It's funny how much my KD has increased from playing so much Hunted in the past month. I seriously feel almost 0 lag both at my house (port forwarded wifi) and at college(hardwired ethernet) on Hunted and a little lag on regular Free-For-All.
It seems the biggest lag problem is when you get a clan/party in your lobby on the other team. Typically they'll all live in a community nearby each other and will likely have host, so then they just get that nice advantage since they'll be playing against 4-6 other people for whom the data needs to transfer a much longer distance to. Free-for-all eliminates parties and clans. Plus, maybe Hunted is so lag-free because there's not much going on? Ex. Only a few weapon crates, each person has one gun at a time, just less for the game to load? Who knows, but I'm definitely not imagining it! 1.2KD to a 1.49KD thanks to playing Hunted, and a little bit of other game modes the past month.
It's just funny seeing people with high KD's because they play Domination/TDM with parties/clans and just leech the connection. Sure, they're probably good, but without that lag help, there's no way you have a 5 KD lol. Anything over 2 really just shows the connection is usually on your side. Even funnier thing is the highest KD I've seen in a Hunted FFA lobby was like 2.2, and I've been playing it so much. 99% have .4-1.7 it seems. Just shows that the lag isn't as bad in that game mode.
ALSO - NEVER play split-screen online. The lag is so atrocious. Just unplayable if a clan is against you then.