Only One Chance
You only get one chance with business clients and strategic cooperation.
Unlike B2C, where there are plenty of small fish, the amount of big B2B fish is limited, and they never forget a mess up.
If you get your chance, build the best offer, think, brainstorm, follow up. Get it right, or at least not disastrously wrong, so you can get another shot. All you need is another shot.