I feel like my insight is meaningful because the large majority of us aren't pros or masters players with 200+ apm. The things I'm going to suggest are principles any of us normal players can apply. Here are 5 things I've done to turn my luck around in ZvT listed from most important to least.
1. Scouting. When playing against Terran it is vitally important to have complete map control at all times. Terran is built to hard counter everything Zerg has one way or another. You HAVE to know what your opponent is doing to ensure you do not build units that will be hard countered. This means overlords everywhere to catch drops. Sacrificing overlords starting at 6 minutes to see their tech. Using overseers after lair. Lings all around the map. Overlords pooping at expansions. You have to know what is coming at you and when or else you will lose almost definitely.
2. Investing in static D. I've starting dropping 1 spore and 2 spines at every mineral line after the 10 minute mark. I simply don't have the ability to manage Terran drops cost effectively using only units. Hellbat drops, widow mine sneak bys and drops, marine drops, etc, require at maximum 5 actions from the Terran player per drop. To deal with these drops without static D simply requires too much apm. You need to run away and split your drones. Tell your queen to attack the medivacs. Split your army to get a surround. Attack the drop. Then put your drones back on minerals and fix gas. While you do all of this there is most likely 1 or 2 more drops happening or a death push incoming. Static D at the mineral line frees up a ton of APM and buys a lot of time for your forces to run around stopping all the drops. One spore in every mineral line by the 8-9 minute mark will help with the initial drops immensely.
3. Creep spread. ZvT is very fast paced and Terran controls the pace. The faster you can move anywhere on the map, the less far you will fall behind. Creep spread will help you deal with drops, get surrounds, and bait widow mine shots into marine packs. Engaging Terran not on creep always favors Terran. The more creep you have the more you even the playing field.
4. Proper reactions to Terran openers. I drone scout every ZvT at 13 supply. It is pivotal you get in their main before they wall off so you can see their gas and what comes out of the barracks first. Reaper openings warrant extra lings and maybe even a spine or two. One rax expand means you can drone safely and take a fast 3rd. If CC first you can even double expand before pool. My point is, Terran has a lot of different openers. If you react incorrectly or don't react at all to their opener, you have already lost.
5. Upgrades. Not much to say here. You can't beat any Terran army with anything if you are behind on upgrades.
There are a lot of threads and guides about builds. However, I've found that no build works in ZvT with out executing the things I've mentioned above. Tomorrow I will edit this post with a couple replays.
Thanks for reading and I hope this helps some of you out.