#1 CLEAN YOUR EMAILS
create a better “looking” email. this means the email looks better to client and server spam checkers. include a SMTP HEADER with valid info. don’t send HTML emails!
#2 SMTP SERVER
user a 3rd party email server.
i’d really recommend using Gmail if you send < 500 emails / day because it’s free and solid. switching over to a paid solution should take minutes
google search for another SMTP provider. here’s some i found:
should be pretty easy to configure sending through these solutions. some of them provide nice API’s. as well as whitelisting, email monitoring, dedicated IP’s, etc…
#3 BLACKLIST MONITOR
subscribe to a blacklist monitoring service.
if you do #1 and #2 you shouldn’t have to *worry* about email delivery again!
do #3 to make sure you stay off any lists.