I think the easiest way is to use premium picks to draft Dmen. Take Nashville who is very good at drafting and developing Dmen. Hamhuis, Suter, Klein, Weber, Josi, Ellis, Jones, Fabbro, and Girard were all top 50 picks. Take out Weber and they are all top 40 picks.
In the same span, the Canucks used top 50 picks on Allen, Koltsov, Bourdon, Ellington, Sauve, Juolevi, Woo, and Hughes. Allen, Bourdon, Juolevi, and Hughes being the only first round picks. If you include 3rd round picks, the Canucks have drafted a bunch of busts but also Edler and Connauton.
Statistically speaking you're more likely to be able to draft top 4 Dmen later in the draft than top 6 forwards. At the same time, if you don't use premium picks to draft Dmen, you have to acquire them other ways which can be difficult. The Blues won the Cup last year with a D corps made largely of guys picked in the first 3 rounds. Washington had some late round/undrafted guys but their main guys were former first round picks.