That's the easy bit but what comes next is where most people fail. The Follow Up - the bit that puts the 'work' in networking.
What's that, you've emailed them all? 'It was great to meet you at the Business Show last week......'. Do you seriously expect people to just reply and give you business? The most likely outcome there is silence, no reply. The trick is not to accept silence as a 'no'. Set aside time to call them, all of them. Don't do it all at once, it's tiring so just make a few calls a day.
The outcome depends on you and how you react. Again the most likely outcome won't be positive but unless you're hearing the word no what they are saying is 'I'm not ready to buy yet'.
That's good, all you have to do is wait fir the right time. Agree to phone them again, and, as you like emailing so much, maybe even send them a message to confirm this. Finding a new client can be a long process, you've just got to be patient.