The best tip is not to carry, or play a solo lane. play a champ that makes a difference. i got this from a 2.1k elo player. By difference, i dont mean gangplank even if he's solo. Amumu, Shen, Malphite are my favorites, and others could be Udyr, Alistar, Janna. you dont always have to carry
At 850 elo you cannot rely on other people to play well. I used that logic in my placement games - my first game I went support taric because our adc picked sivir. Taric Sivir is a murder combo due to being able to stun + boomerang blade. Too bad my sivir was a complete r-tard and was spamming boomerang blade on creeps, always running out of mana and never was ready to use it on a stunned person. I was completely cordial and suggested she use it on the stunned people but she insisted she knew how to play - this was proven inaccurate when she rushed a manamune. Fortunately the other adc was equally as derpy and our mid carried us. After 2 games like this I switched to playing adc myself and finished placement 8-2.
Once you get into the 1500 elo ranges where you start to get competent people playing lanes then you can move into a support roll and really feed an ADC kills. I have played with an alistar and blitz who were pro at setting up kills bot lane and the game went nuts with me being 6-0 with 150 cs at 20 min mark.