Stop playing Zed, Yasuo, and Lee. If your goal's to climb, you don't need more mechanical champs to win games.
Tanks/bruisers that can have an early presence or a lot of mobility/cc in the jungle wins games, which is arguably the best carry role atm unless you learned how to roam well as a mid. Don't spam ranked, and don't accept surrender votes unless the game is 3 - 20 all towers but base taken. It's low bronze ffs, throws WILL happen. Besides, you won't learn jack on how to turn games around and capitalize on mistakes if you end the game before it happens. As a jungler, you especially need good map awareness. Spotting things like: my top laner's getting ganked, I can't get there in time, but my bot lane's doing well/their bot lane recently backed; let's sneak in this dragon.
Do NOT gank your 0/4/0 top laner or mid unless your cc is enough to halt them from doing damage long enough for you to kill them.
e.g.Trying to 2v1 a Darius with a few kills on him already is mad risky; that's why you want to try to have some early presence on champs like him so this doesn't happen. If it does, don't worry, he doesn't really do much in fights. He has no gap closers and he'll blow up with grievous wounds on him. If your mid doesn't have them, try to get your ADC to buy
and sit on it for a while.
You really need to keep all the small things in mind, like power spikes, levels and stuff before making decisions. That's the hardest part. Otherwise you're usually just farming it out in the jungle for a bit before looking for your next gank. If bot's pushed in, health/mana/levels are about even and you're playing Vi or someone with an easy gap closer, stop farming the damn chickens and go for it.
Malphite jg was my go-to for plat. Team just had to give me a chance to hit 6, and I'd have a presence every minute. R-to-win, no mechanical prowess required. Veigar support too. It took maybe 80 games from P5 -> gold 2 place -> g3 -> P4.
Seriously, hate the surrender button with a passion. Rather climb in 80 games of various lengths (25-45 minute) than try to grind 300-500 games in only to reach last season's division. You'll find it a lot more rewarding and end up saving loads of games -> promos you'd otherwise have to frustrate yourself over.
Try not to duo too much; tends to saturate your MMR and eventually leads to mediocre LP gains/losses before you even hit a 50% winrate. And if you do, play with someone Around your skill level (not just elo; no high plat smurfs) in a different lane. So that way assuming you can both hold your own, if someone's feeding their ass off (it will happen regardless of what we say/do,) at least the game's carry-able. But if TWO people are feeding :^) well, it probably won't be lol. Shrug it off.
Lastly, wins/losses. Just stop at 2-3 losses in a row for the day. The. Day. One hour isn't going to freshen your mind; you're gonna need a goddamn nap if you actually want to forget about the last game. If you're on a winstreak, nice, but again, don't grind a shit-ton of ranked either. Get some fresh air god damn it. You can always stomp the next day. And don't feel bummed out if your 4-game winstreak does end. I've come to realize, through my experience anyway, that winning too many games in a row just before promos will reciprocally increase your chances of losing games during that crucial time. Otherwise there's no reason to sweat promos.