EPTIf you see him going roaches, make some drones and then keep the roach count as high as him, you should have speedlings to keep tracks of his roach numbers, the idea is to get an early drone advantage and then use your ramp to hold the few extra roaches he could have.
If he goes ling baneling you should place a spine crawler and make baneling drones, use 2 banelings to kill his baneling balls and, a few lings to stop his baneling picking lings, you will need good micro. In maps you cant do this you must do the same but have way more lings and make some drones from time to time.
I always recommend going roach hydra infestor, i think its better than muta but thats only my opinion, with +1 range attack your roaches can kill his lings in two hits and you can use fungal to kill every ling bane muta, the trick here is to not make a lot of defenses early, 5 hydras and 3 queens can handle mutas quite well, pump a lot of drones and make sure to have around 3 spores per base once you leave your base.
Once you engage you will need about 5 infestors, use 1 fungal to deny his mutas, if he swithced to roach hydra too you should have a lot of hydras and only a bunch of roaches to tank, fungal his roaches and abuse the range of hydra to have free hits.
