What should a Bronze player be doing pre-season to climb?

So I am a Morgana/Lux support main (Lux very recent, a month). I have a >50% win rate with both. I think I'm pretty good at rotations (I could be wrong but I consistently get shot caller honors if that means anything). I do admit I'm tilted easily. I'm ashamed to admit the last few matches of the season had me flaming my teammates mercilessly and I'm trying to stay away from that kind of behaviour and being calm. I have consistently been bronze for 2 seasons now and I really want to change that. I used to play with my SO in s7 and a break up kept me away from league. Pre-season, should I focus on picking a role that has more impact (I'm thinking ADC/Mid. Can't stand being top/jungling) or should I work on polishing my support game? Any and all tips are welcome. I'd also appreciate it if you took a look at my profile and let me know where I'm going wrong, though that's not completely necessary. Thanks in advance guys.
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