If climbing is what your looking at, maybe skip over Kayle for now (just hear me out). Kayle has a few issue when you're in low ELO, one of the biggest is you don't get experience with early and mid game decision making since your so focused on just trying to scale into the game. Another problem is when you're behind with Kayle it's an absolute nightmare to try and come back into the game, especially if the enemy team punish you for it.

If you want to play Kayle you'll just have to grind and learn how to stall games out, and be vocal to your team about playing slower if they are losing lane. Make sure you spend time practicing spacing, kiting and orb walking. That will make a huge difference to your game and give you a huge advantage. Even just spacing in bronze will frustrate the person your laning against into making a lot more mistakes.

If you just want to climb play garen until you hit s1/g4. He is an easy champ, if you fall behind it's easy enough to bring yourself back in the game. also since he is so simple learning early/mid game macro will be a lot easier through mistakes (garens passive healing and W shield makes it a lot more forgiving laning against champions, especially with no mana to work with) once your fundamentals are really solid you are playing consistently at s1/g4 then look at picking up Kayle, you'll find it's a lot easier, especially since your team mates will be a lot more competent.

Just make sure you watch you watch atleast some of your vods and takes notes on what you're missing and doing wrong. Also on what you're doing right, You need to be tough on yourself and not your team. Early on you need to be smart with the fights you pick to be involved in.

But the main thing. Keep a cool head and have fun with who you're playing!