Date for a few years.
Don’t move in unless both of you are extremely serious about living together. Even if there’s a lot of love in the air, enjoy the times when both of you are apart and miss each other, and take things slowly. Moving in together should be a step that should be considered seriously and only as a step before marriage.
Living together is not a test.
This is the worst mistake that many couples make. If your main intention of moving in together is to test the relationship, you’re bound to find flaws and differences that’ll tear the relationship apart. Don’t look at living together as a test, look at it as a preparation for marriage because both of you are already prepared to commit to each other.
Behave like a married couple.
Take each other and the relationship seriously. Prioritize your life and be willing to change for the relationship and for each other.