Base build:

10/10 Overpool (Pool after overlord, Pool is put down when Overlord finishes basically)
11/18 Scout with Drone
Drones to 13/18
13/18 Build 4 zerglings, 1 Queen
17/18 2 more zerglings when this larva pops
- be aggressive with 6 first lings
18/18 Overlord
18/18 Extractor when the next larva is about to pop (11 seconds after OL). ---> 17/18 supply.
17/18 Drone

Important: Right before your lings arrive to his base/ramp your extractor will finish and queen pops out. Remember and practice this timing to put 3 drones on gas and do larva inject. Keep building drones and try to sneak inside his base.

Variation 1 (opponent opens early cybernetics for early mid game rush):

20/26 Hatchery (expansion)
25/26 Overlord (make only drones)
~28/34 Lair (use first 100gas to make lair)
Keep making drones.
Add sunken if playing blind or vs confirmed rush.
When Lair is 2/3 to 3/4 finished add second extractor.
~34/44 Hydra den (lair finishes)
Drones to ~37/44
Overlord, then stop producing!
~37/52 You should be able to make 4hydras simultaneously, followed by a quick 5th.
Add 3rd extractor.
Hold off the rush and power drones.

Variation 2 (opponent opens 2gate or any other early game aggression strat):

Stay on 1 base.
~21/26 Roach Warren (drones up until 21)
Drones until ~25/26
25/26 Overlord
25/26 Zerglings.
26/34 3 roaches
29/34 If he is being passive make drones. If aggressive more roaches.
~31/34 Lair
~34-37/42 (depends how many units die etc) Hatchery, expansion

If you are sure you can kill your opponent skip lair and keep massing roaches. If you want to be safe (recommended) switch to mass drones and only threaten an "all-in" with your roaches.
If you don't go all-in, and power drones, transition into hydras after lair finishes.

Observe: Timings are relative in variation 2. With aggressive openings units will die.