Some of the factors that help you build a good reputation faster and increase deliverability are:

• Limited spam complaints and bounces.
• Including the ability for recipients to unsubscribe.
• Recipients interacting with your emails in a good way: reading, replying, forwarding and adding your addresses to their contacts.
• Paying attention to feedback to slow or stop sending for a period of time.
• Having good content (see below for more guidance on content).

Also, consider letting your users to reply to your emails. Having a meaningful email conversations with your audience will do wonders for your reputation as a member of email community.