The requirements are:
Maxed Cyclone
Maxed Vertex
It is also recommended:
Maxed Avia Production
Rank 15 or higher
Enemy doesn't go for too many Hawks
Build your buildings in the following order: (in 1v1)
2-3 Barracks (depending on the map)
1 Power Plant (if possible while previous upgrade is not finished yet)
Assault Vehicle Factory (if possible while previous upgrade is not finished yet)
2 Avia Factories (if possible while HQ3 upgrade is not finished yet)
1 lvl 1 Avia Factory
1 lvl 2 Avia Factory
1 Airfield
Build your buildings in the following order: (in 2v2)
Same build order as for 1v1 until first Avia Factory is built
The player who goes for Vertexes now needs only 1 Avia Factory
The player who goes for Cyclones no longer needs an Airfield or lvl 2 Avia Factory
The first step is to directly go for HQ3 while not neglecting economy as described in Build Order above.
When using this tactic without the help of a partner, the goal is to have Cyclones take the damage of Anti-Air Towers and Porcupines so Vertexes can attack without getting hit by it. Because Cyclones are relatively tanky with low damage output compared to Vertex which have less HP and Armor but in turn a far superior damage output.
One key aspect to make this work is to always place the Cyclones on the side of the enemy base where the Vertex will then attack directly afterwards as otherwise there is still a chance that the anti air of the base will target them instead. Here, timing is also a key element, as this tactic is perfectly executed when Cyclones only reach the enemy base directly before the Vertex start attacking. The primary target to attack should always be Anti-Air Towers and Porcupines as this will allow your avia to keep down the air defenses permanently once they are first destroyed, at which point victory is more or less assured.
An additional benefit of this combination is that Cyclones are capable of revealing Chameleon, which in turn allows Vertex to directly snipe it even while activated, making this tactic very versatile.
This tactic becomes even more effective when used as a team, as 1 player can fully focus on building and micro-ing Vertex while the other only needs to control Cyclones, making it all the more effective.
It needs to be noted though that in late-game it can be a good idea to switch to Vertex and Thor as this tactic can harm even the most heavily defended enemy bases. Additionally it needs to be mentioned that Heavy Assault is a good support unit for Cyclones, making it worth adding at some point during the battle.