by ND3G
Well, aside from opening moves there is really no set strategy you need to follow.In your first move you could play:
March -1 to move your ship from Redwyne Straights to the West Summer Sea
Consolidate Power in Dornish Marches
March 0 in Highgarden to move the footman to Oldtown.
With the knight you have a couple of options. You are second in the fiefdom so you only need to play a 3 strength card to push Baratheon out of the Reach or Martell out of Starfall (assuming they take them), or you can try to up your supply by taking Three Towers or Sea Road Marches. Lastly you can take The Arbor if you want a Consolidate Power factory.