Hello, I'm a long-time League Of Legends player HyperFake. I'm playing league since s3. I started by playing a lot of top lane champions. For some time I was Riven OTP (one-trick pony). Playing almost only riven reached diamond, but then got bored of the champion. Since then I'm more into bot lane gameplay. I think that bot lane has almost the same amount of responsibility as jungle when it comes to game-winning. Since season 10 started drakes are a really important asset to the team and only bot lane can provide protection of it. Caitlyn provides early domination of the lane thus drake protection and gold tower.

Pros - Caitlyn is a long-ranged champion so it can out poke almost any other champion in the game. She can deal quite big damage with combo e + q + basic. q provides lane push. W is a really great spell when it comes to ganks and counter ganks.
Cons - It's quite a slow character. She only has one spell besides her flash that can help to escape, but it does not provide a big dash and it's not fast. Cooldown is pretty bad in the early game too.

Synergies - Morgana is #1 champion when it comes to support. Her q is a great way to set a trap under someone. She can deal good amount of damage and even stun with her ult. She can shield Caitlyn so she can escape, that is a big one of the biggest plus.
Later we have root supports that have some kind of cc. Zyra/ Lux/ Thresh. While Zyra and Lux can deal a lot of damage, they are quite squishy. Thresh is quite tanky and can take almost all damage while trading in the lane. He is also very great when it comes to ganking or counter ganking.

Counters - Senna is probably the nightmare of all adc's. She is support, but she deals more damage than enemy adc. She can heal enemies and has quite a big range. Her ult is almost instant and can provide shields to enemies around the map. She has a root with a very long range so dodge by going to side, not running in a straight line.
Second would be Swain. If he catches you with his e, you're in danger. The root is long enough for enemy adc and him to deal a lot of damage to you. Even if you e out of it you just lost half of your hp. Playing against him try to predict and dodge whenever you can his e.

This rune build is tanky. Taking will provide you with some kind of anti-burst support. So you may not die from assassins one-shotting you. is a great way to increase tankiness of adc. Just adding health to your health pool is never a bad thing.
You can choose between and but, I would strongly suggest taking bloodline to have early sustain and the ability of not buying life steal for most part of the game.

Once you go 100% crit, you don't want to go back. Having standard build with 75% or 50% crit is just bad. It's up to rng gods to decide if you're going to crit or not. Many enemies have survived in the past because of me not criting enough with 50% crit chance, so 100% crit is a really great thing. Besides, remember that adds 25% damage to every crit you make. This is why 100% crit is worth it even more.