I use Zapier to connect CRM systems with email marketing systems. Check to see if your CRM and email marketing system is on there. If it is, you can save yourself a lot of time.
I agree with the other poster that segmentation is critical. Find out as much as you can: buyer or seller, price/budget, location, etc.
I use Active Campaign for this type of thing as you can set it up to tag people automatically.
Disclosure: I'm a partner with Active Campaign and internet marketing consultant