The phrase "a main tactic" is correct and usable in written English.
It can be used when discussing a primary strategy or approach in a particular context, such as business, sports, or military operations.
Example: "Our team has identified a main tactic to improve our marketing efforts, which involves leveraging social media platforms more effectively."
Alternatives: "a primary strategy" or "a key approach".
Scapegoating the less assimilated transgender community has become a main tactic in anti-gay activists' playbook, now that they have lost the marriage battle.
A persistent refrain in the fall of 2016 was "I can't wait till this thing is over already". Making Americans want to make the election (democracy) "just go away" is a main tactic of the futility strategy.
A main tactic was to demand a "Fair Hearing" before welfare department officials at which a welfare recipient could make her case.
A main tactic that an emotionally abusive parent wants is for you to apologize to them for them abusing you.
However, suppression is still the main tactic when a fire is set by a human or if it threatens life or property.
Difficult airway algorithms begin with a decision of 'forced to act', which necessitates an immediate best possible attempt, or 'not forced to act', where the main tactic is an awake intubation.
Neilson's main tactic as a director seemed to be to draw his actors into an unspoken conspiracy.
We thought that the flooding of web sites, talk back radio, television chat shows, letters columns in newspapers, blogs, with tens of thousands of mindless repetitions of a few talking points, was the main tactic.
His main tactic was to mock a man who supports the use of deficit spending during a recession.
The main tactic employed by his opponent, a comparatively lardy American, looked to be working the home favourite into a corner and then slowly squeezing the life out of him with his big belly.
Nonetheless this is a much more rounded side than the team whose main tactic earlier in the year seemed to be to break at speed.
