To master a champion? Just spend a lot of time on it.
Honestly though, if you're stuck in Silver, I think it's more likely that the fundamental skills you're supposed to be developing at this skill level are lackluster. I can that you're mostly a bot lane main, and that comes with a lot of responsibilities. Do you assist your team in taking towers? You're the one best suited for that sort of job, you better be on that. Are you helping your Jungler control Dragon? The main reason why the Bot Lane duo is Bot instead of top is because Dragon exists, you're wasting a lot of strategic value if you guys don't control it well. Are you building based on the situation to help shred Tanks for the rest of your team? As the ADC, it's your job in a teamfight (most of the time, depends on the ADC sometimes) to be killing the Tank. Or, as a Support, are you properly defending your ADC from the enemy team's greatest threats towards your Marksman?