Honestly man, the #1 thing I would do is scout out my teammates before the games begin. If you get some thats been on a massive losing streak (like 1 or 2) and nobody else seems to be consistently putting out a solid KDA I would just try to dodge that game.
Dodging was a huge factor in me making a quick climb to gold this year, sacrificing 3 lp to reroll for a better matchup is worth spending it towards hopefully making bigger gains.
Also I would broaden my champion pool, galio is a decent support but he doesn't have a big amount of great matchups (about 13 of 29) in the bot lane (support main myself), I wouldn't necessarily pick him into a blind pick situation because almost all of the hook champions beat him pretty hard and they are probably the most commonly picked.
Looking at the op.gg, it looks like we're averaging over 10 deaths a game, if we want to climb we have to be more picky about the moments we choose to engage. Play around enemy cooldowns, check out skill CD's before the match and look for windows to attack when their key abilities aren't available.
Also try to make it a habit of glancing at your minimap when there isn't a ton of action in the bot lane (i.e. the adcs are just farming heavy) and make note if you see an enemy missing and ping it if you can.
For the later game, ward around objectives if its safe to do so, try to stay in proximity of two or more players close by. Grouping is a huge must in the latter parts of the game. Be careful if you think an enemy is alone because its possible you might walk into an ambush.
Think about what the enemy is trying to do currently and possibly in the future. If you have a pretty good idea of what they may plan to do that will give you an opportunity to counterattack accordingly. You may still have a shot at gold this year but if you don't hit it use pre-season to give yourself goals of what to improve on and carry into next season. Wish you all the best pushing for that final rank.