Help getting out of bronze

Im and adc main, but ive practiced with every role so I can play anywhere decently. Though ADC, sup, and jungle are my best.

Recently ive been on a hell of a losing streak in ranked and normals. (The normals I dont mind because I try to use those to get better.) Anyhow, I recently decided to try my best to get out of bronze, but thats quickly going to shit. Im losing all my games and just cant seem to do anything in ranked or normals. I can position fairly well, not the greatest, but its getting better. I have attack moving down for the most part, and I try to regularly practice last hitting in custom games. (I play Vayne a lot mainly for the self peel, I also like Lucian, Graves, Sivir and Jinx.) I think I ward well, I buy wards often and just try to keep wherever I am warded to avoid ganks.

Im trying to stay positive, but im getting so tired of losing and sitting at bronze 5 since the season has started. What can I do to get better and win more often? Any advice is much appreciated.

Here`s my Opgg if it helps any: Sxli Op.gg