There is a lot of unpopulated, very fertile land in the region south of the Firth of Forth. Offer some of this land to wealthy and powerful Anglo-Norman nobility. Build more monastries to bring Scotland up to scratch with England's religious communities.
This is a little hasty. You have limited power in these areas and it would be too dangerous.
Find a nice young debutante and marry into a powerful Anglo-Norman family. This will lend you political alliances and may encourage them to join you in Scotland.
Which card will you play?