u/Earthquake1000000

I run a pool of champions in mid lane mostly, and I don’t fully understand team comps enough to know what to pick outside of countering my lane opponent.

Aside from hard counterpicks and obvious choices, the main question I struggle with is whether to pick Ekko or Leblanc. They both provide their own value but I don’t understand the difference and when one is better than the other.

What guiding points should I use to try to figure out who to play, that preferably can be applied not just to the two of them but to all champions?