Not a lot of ranked games to go off of, but a few things that could help.
as support you are going to want to buy a sightstone. Vision is key, and although it is more team based than it used to be Sightstone will still allow you to put some wards on the map. Also, don't forget to place a pink ward. You can look up some pro guides or videos on good places to ward. I know I still waste some wards by putting them in dumb places, trying to stop doing that. Lux is my main mid but I hate playing her support so not sure the best suggestions to tell you for playing her support.
- Looks like you have had a good amount of deaths in your few ranked games this season. You average 10.8 deaths a game. You are going to want to try and play more safely and use your map more so you don't get ganked as easily or run into traps or get caught out.
- Never hurts to work on practicing csing. I have played thousands of games and played this game for years and I am still pretty bad at it.
- Look for opportunities to take objectives such as towers, drags, baron/rift herald, etc. The lower elo you are the more inclined a player and his teammates are to lack focus on objectives especially killing turrets. Bronze games on average are the worst where a lot of games turn into team death match where everyone is going for kills and fighting all the time and forgetting to try and push down turrets.
Just some quick things to think about. There are a lot of ways to improve so hopefully other summoners can provide you some additional information.
Don't be afraid to learn from your mistakes. Instead of getting mad from losses try and figure out what you could have done better to help your team win the game. It is really hard if you have afkers or trolls in game but the only way to rank up is to improve.