Dealing with supply block as zerg

So pretty basic question but how do you guys avoid getting supply blocked? Do you have a rule of thumb where you build X overlords at a time or something?

I don't get supply blocked too regularly but it happens often enough that I feel I need to fix my problem.

I normally build my overlord when I have 4 or less supply left.

My starting BO involves:

• 9 Ovi
• 16 Ovi
• 22 Ovi
• <4 Supply left.

I think this really helps.

Additionally if Larva have popped from one of my Hatcheries, I usually spend 1 on an Overlord if I'm going to use the other 6 on units.

Hope this helps.

Keep an eye on your supply and build an overlord a few supply early each time. The main thing is to make sure you watch your supply. It takes some training and some mistakes that you're going through, but really you want to avoid having to construct multiple supply units at once; it's much more efficient to construct them as necessary.

If you use the Queen "spawn larva" ability, you have every time after they spawn seven larva. select the hatchery and select larva. then, click in the beginning once V for overlord, then build the rest, type Z for zerglings, etc. so you won't forget. (V, Z * 6 or V, R * 6). if you build heavy supply units, like ultralisks, press V twice. this way you will never be supply blocked. (if you run low on minerals, or if you see you have a lot of supply unused, stop building overlords for a while). you have to build your overlord first, because if you have used all your larva, you will not be able to build the overlord right away, but to wait until a new larva spawns. and that takes a lot of time.