Looking at your op.gg its pretty obvious you won't be able to make it to diamond without significant time invested in improving your skills. And, to be perfectly honest, you (and I mean you specifically given the stats I'm seeing) will never accomplish this from mid lane. You simply lack the appropriate skills. An average diamond 5 player manages double your cs per minute (a good indicator of top notch mechanical ability, in order to farm well you need to master last hit mechanics, wave clear mechanics, lane trade mechanics, backing and timing mechanics as it relates to the flow of objective pressure and control, and specific matchup mechanics.) That's 12 months worth of hard work and improvement ahead of you to get to that level that you simply can't compress into a 3 or 4 month stretch to make a real run before seasons end. And none of this takes into account general gameplay mechanics and knowledge like teamfight coordination, objective and map control, compositional knowledge, power spike knowledge, game flow experience and knowledge, strategic knowledge, tactical knowledge, etc, etc, etc.
All this being said, don't set that kind of goal for yourself. It can only lead to frustration. Instead, look to set smaller short term goals that are achievable and look to make improvements in your overall play each and every game. Instead of setting the goal to "try to hit diamond" (which, again, for you will be impossible this season) try setting a goal of winning 7 of 10 ranked games this week, or managing a 7 cs per minute or better average for your next 5 games, or dying less than 5 times in your next 10 games. Smaller short term goals like this are better at improving your skills at the game because they are goals that CAN be achieved reasonably and in a short time frame while simultaneously enhancing your skills in the areas needed to reach a much loftier long term goal of achieving a ranking in the top 1% of the ranked player base. Additional information regarding tips and tricks for climbing the ladder can be found all over the board, and, as a diamond player myself for several seasons (recently quit, this is a bad game, but that's up to you to figure out on your own) plenty of the tips and tricks you might find have even been stated by me personally. A simple forum search for my name and "PSA regarding ranked placements" will bring up an article posted by myself in which a great deal of information can be found not only in the OP to help you reach your goals, but also in the comments as questions were asked and answered and information divulged from a reliable top 1% player source. Another great tips and tricks poster to check out would be Commando Yi, a jungler specialist.
In any case, best of luck mate, work hard and set realistic goals for yourself and you will quickly find yourself achieving the levels of success you desire.