Email marketing must be part of your inbound marketing strategy. It will help drive traffic to your website, leads for your business and provide personalized value to your community. HubSpot provides all of its customers with email marketing tools that let you send up to 50,000 emails to a list at once. You can use HubSpot's List Manager app to slice and dice your leads and customers to send them personalized, segmented email campaigns.
However, one thing I recommend everyone set up is an email seed list. A seed list is a list of email addresses that you will send an email to before you send the email out to everyone on your list. A seed list allows you to test the email across different email clients and devices. This will give you the ability to measure the email's deliverability, appearance, and make adjustments before it gets sent to everyone on your list.
You should create an internal seed list composed of co-workers, friends or family that can help you test your emails. I would include at least five or more people on the list and try to find people that use different email clients and have different mobile devices. The goal being to test your emails on a variety of different email clients and devices.