There is no single best way - that said I prefer to keep in mind that businesses owners get inundated with offers.
100's of emails every day and week - so what are you going to do different..?
Instead of cold emailing - just like everyone else - why not set up a webinar and speak to people en mass.

This will leverage your time and your potential reach from 1-to-1 to 1-to-many.

Instead of humping for business - like everyone else - what will you do different to get their attention..?
could you walk in to local brokers?
Perhaps send something through the post
Build a relationship first..?

At this point - why would anyone open their client books to you?

You may well be surprised that money is not the only motivation - Doing business with people I like is a big motivation for me.

action steps - change the way you do business
get people on a webinar
promote your message to a mass audience
let them apply to work with you
Most of all - build relationships

Hope that helps
Regards
Phil

ps - call me if you need help with setting a webinar strategy like this up