Everyone wants to rank up, only a select few will put in the work. If you truly want to get your dream rank I suggest you start a training routine.
What is a training routine? A training routine is what you do in order to improve, you usually do the routine either before your warm-up, or after your ranked session.
My recommended routine is quite long at around 2 hours, but you can shave off some stuff if need be. I will link my recommended training routine in a Youtube video below.
For warming up before ranked, you want to have a set routine for that aswell. However, instead of 2 hours this routine should only be around 10-30 minutes. This just helps you to be more consistent in game and whiff less. There are plenty of warm-up routines you can find on Youtube aswell as other places. I don't really have a favorite so I will allow you to search for that on your own.