The event is the excuse, not the strategy
Trade shows are the most reliable business-development opportunity in most specialist markets and the most wasted. The usual pattern is: attend, walk the floor, collect cards, send a follow-up that looks like everyone else's, and get nothing.
The exhibitor list is published weeks in advance. It is a pre-qualified set of companies who have paid real money to be visible in your sector on a specific date, and it is sitting on a public web page. Working it before the event turns an expensive week into a diary of booked conversations.
What you get back
A table: company, whether they exhibit or speak, the stand or the talk, whether they fit your profile and why, the decision-maker with title and verified work email. Plus two drafted touches per target, held for your review.
Why qualification runs first here
A mid-sized trade show lists two or three hundred exhibitors. Perhaps twenty are relevant to a specialist desk. Finding contacts for all three hundred costs real money and buys you a list you will not work.
Qualification is free, so it runs on the whole list before a single contact is searched for. That ordering is the difference between this play costing very little and costing a lot.
Variations worth knowing
Run speakers separately. They deserve their own approach. Referencing someone's talk is a genuinely strong opener, and it does not transfer to the exhibitor list.
Run it on last year's list too. Companies that exhibited last year and not this year have often changed strategy, which is its own conversation. Companies that exhibit every year are committed to the sector.
Follow through afterwards. The same list, with a different second touch, is a decent post-event sequence. It works far better when the first contact happened before the doors opened.
Where this goes wrong
Leaving it too late. The whole value is being early. There is no version of this play that works the week after.
Not qualifying. An unqualified exhibitor list is a mailshot, and the recipients can tell, because everyone at that event is receiving several.
A generic meeting request. "Are you attending?" is not an approach. The reason to write has to be specific to them, which is why the qualification reasoning is kept and handed to the copy step.