Never try to close a deal on email

Firstly you lose control, increasing the chances of being ignored or ghosted.

They will most likely have further questions or objections that you haven't flushed out properly.

There may be new people in the decision making loop with new objections you are not aware of.

Make it easy for people to say yes. Guide them, help them and lead them.

People don't want to buy or make a change unless they feel absolutely compelled to do so, and will look for any excuse not to move ahead.