Although it took me one and a half years, I finally got diamond after being placed in iron 1, and I think this is one of the most important tips for climbing.

FIND A GOOD DUO THAT WILL ACTUALLY HELP YOU IMPROVE. I solo-queued to plat and was floating around plat 1 to plat 3 for about 3 acts, and when I started duoing with a diamond friend, I thought I was guaranteed to climb because there was one more person on my team that was guaranteed to be good. After 25 games, we had a 30% win rate together. After I found a new duo (who I have a 65% win rate with), I realize how important having a good duo is. The first duo got tilted easily and shit talked my teammates in our private VC, reinforcing the idea that I wasn't the problem and my teammates were. My second duo was a random that I added while I was solo-qing. He always kept a positive attitude, in team chat AND private VC, which helped me and my teammates not get tilted. He never back seated me, but helped me look back on my plays and learn from what I did wrong. He helped me how to use my utility and at what times, and how to peek better as well. I've duo'd with this person for a little over a week now, but feel like I've learned more than in the whole 3+ acts I was in plat. I can't emphasize enough how important mental is in Valorant. Having someone that can keep you grounded when you start to get tilted and not feed into it will help you immensely. And remember; if you play to improve and NOT for elo, your rank will come with time. I hope this helps for anyone that got placed at a low rank hoping to climb.