1) Live alone for sure. People need to spend time learning who THEY are before they can become ONE with another person.
2) Get tested. Seriously...it's better to know before than after. And perhaps you may have not known you had something and never saw the signs. But at least you'll both be on the same page.
3) I don't think it's completely necessary to "sleep with each other" but I does help
4) Go to pre-marriage counseling
5) Meet each others WHOLE family!!! VERY MUCH A MUST!