Without any specific information, it is hard to give advice that will be specfic for you. I'd say though that if you happen to experience rage / tilt in game, try not to actively yell at your team mates. Compliment them any time they do something well. This raises team morale and makes you more likely to win.
If you find you are dying too much, keep in mind things like vision, where and when you last saw the enemy jungler, and really gauge / think twice before chasing a low health target. Can you really catch them, or are you asking to get killed by turret / turn around / gank?
Focus on perfecting your CS. Getting high CS amounts alone should get you to high silver / low gold.