Just to push you further in the right direction - you need to decide what you want the email to accomplish. It should do that and no more.

Often you want them to arrange a consultation with you. So they just need a taster of your solution that will leave them curious for more in person where you can still adapt it to their requirements.

Once they are sold, stop selling and go for the close. Otherwise you might talk them out of it.

Respect their time and keep communications short. That way they'll read every word.