Level GLD to 34 first to get Provoke, Convalescence, and Awareness. Flash is also pretty nice in some cases for WAR, but if you level GLD till you get Awareness, you'll have Flash unlocked anyway. Provoke is mandatory, Convalescence is amazing and Awareness is mostly situationnal but very good on WAR.
Level MRD to 26 second for Bloodbath, Foresight, and Mercy Stroke. Bloodbath's sustain is nice even if you'd think it's barely noticeable, Foresight is garbage but it's still one more defensive CD, and Mercy Stroke is both a DPS gain and a very good self-heal if you get a last-hit with it during a trash pull.
If you plan on playing PLD, CNJ gives Stoneskin, but you already have it levelled from what I understand (which is nice).