Don't use wording like "buy now", "free", "get it now" etc in your email. Don't send out spams, just send mails to those whoever expected it (send to subscribed emails, not the scraped emails, etc). Send out emails as slowly as you can - and don't exceed the limit that your hosting allowed.
On the technical side of things, there are a few steps you can take to increase deliverability. SPF records. "Sender Policy Framework" tells email servers who has permission to send email from yourdomain.com. Make sure it is granting permission to the source of your email. This is a 1 minute edit to your domain DNS record. A little harder to set-up, but important enough to bother with is configuring DomainKeys. I also use and recommend AuthSMTP.com for email sending. -Ryan
If you are sending spam email, the easiest way is to buy a hand grenade, pull the pin, and sit on it. Then your garbage will be in the inbox, on the ceiling, and everywhere else once the grenade discharges. Or better yet, use a trusted opt-in email service provider.