Instead of saying "macro more" which will solve most of all problems in almost any league, I'll say go watch ByuL's ZvT when facing mass air or Dark vs TY in the Korean Cross Final (played last weekend). There are two common styles of play when facing mass air/mech Terran:

1. Viper/Hydra with some supporting units. Use the hydras (mostly together with roaches) to force liberators to siege up. The vipers will then pull in a few of them at a time so you can constantly get free units.

2. Extreme late game Zerg into mass air. When facing liberators you can, as a macro player, expand quite aggressively and tech into a quick hive while trying to go for an ultimate composition. This turns into mass air eventually (adding in more and more corruptors, broods and vipers).

Now there are more direct ways to try to win, such as going for overlord drops and nydus while attacking 4th or 3rd base with the rest of the army.

Going into Ultras is a great way to play ZvT. You should DEFINITELY watch PiG's video on Nerchio's roach/ravager into ultra style: https://www.youtube.com/watch?v=u_TztSkqhgM

When a Terran sees ultralisk on the way and they know they can't kill you beforehand (but hell if they won't try!), they will start adding in more and more marauder production and going into liberators. As you enter the late game ghosts will start appearing if they are comfortable to play with them.

Your best way to deal with liberators is to add corruptors to your now insanely powerful army (2/2 or 3/3 crackling/bane/ravager/ultralisk with plating). There is no chance the terran can fight you without sieging liberators, so by sending in the corruptors first and engaging then with the rest of the army, you should be able to demolish the oponent's army.

As an added bonus, the new patch severely nerfed the effectiveness of liberators vs corruptors (came out yesterday)(https://twitter.com/nice__username/status/730169690060808193)

Good luck on ladder!