What it means is you focus on what YOU can do better, due to the simple fact you can't control other players in solo queue. You can try to communicate, but a lot of people don't listen or rage if you say anything to them at all. So you focus on you because what else can you do. But there are plenty of games where there is nothing you can do on your own to make it a win.
Yesterday I had a ranked game, I was jungling, where our mid ezrael fed syndra first blood and 3 kills within the first few minutes. Our top heimer was shoving to enemy tower and so I couldn't gank his lane, and in fact he started to get ganked constantly by the fed syndra roams, and she poops on heimer. I tried to camp bot but enemy had a sivir blitz lane which is really hard to gank, and everytime I did try to gank our bot lane would chase too hard, give blitz a clear shot for grab and get pulled and insta killed under their tower. I politely told bot that just because I'm ganking it doesn't mean they can run up to blitz and get grabbed under their rower range, if they don't see a safe way to move up, back off, I'll back off too and we try again later. Their support started raging and began following me around the jungle stealing my camps while all 3 lanes continued to feed.
Was there anyway I could have turned that match into a win by myself? No. But I still thought about what I could have done better because sadly I have no control over trolls and feeders and sometimes you just get stuck with them.