So you would suggest that I farm a bit more? If I do happen to get in a lane with somebody I normally try to stay with them and do as they do unless they are doing something I don't completely agree with or just goofing off trying to throw the game purposely
Related to that is trying to get farm from build up minion waves in the midgame without leaving your team a man down if a fight breaks out. Knowing exactly how long you can farm lanes for when a teamfight might break out is probably one of the most difficult skills to acquire, since it's always a very precise timing call, and it's something even pro-level players misjudge a lot. I'm certainly terrible at it, and frequently have much lower farm than I should just by trying to be everywhere in the mid/lategame when I should just be farming and trusting my team to not get completely caught. It's another example of the power of wards/map vision to let you estimate whether you can safely farm a lane.
One thing I'd suggest is to do bot games and just see how high you can have your CS while not completely ignoring kills. It's actually fairly challenging even against bots to have perfect CS since they'll try to harass, so it's a pretty good practice regimen.