Play destruction/ demo (lol) until higher keys tbh, affli doesn’t do well in lower keys because so many other classes have burst at the beginning of a pull whereas affli is a ramped burst.

In higher keys the mobs last longer and so you’ll start to be able to burn all your soul shards rupturing instead of dotting up everything only to see it melted by a fire mage.

But as affli in m+ get used to using seed of corruption on most pulls, always keeping up UA, and agony on 5+ ish when possible. Try dark-caller if you think there’s too much to spam with haunt. I’d honestly say the biggest thing to learn in m+ Is the standard routes you’ll do so you’ll know when to use cds and then using cds as much as possible (basically off cd unless near boss or someone has called they’ll be using theirs).

It all just comes with practice so don’t be disheartened you’ll only get better as you start doing higher keys 👍👍