If your goal is to be independent then level them all. Use leves to get to 50 and I targeted repeatable leves personally. Then after 50 if you still have leves do them but otherwise start doing collectibles. The only difference with Collectibles and Leves is you have more forgiveness on a collectible. Of course you would like max collectibility but the minimum rating is often around 50-75% of the rating bar. You should also be able to do the weekly turn-ins starting at 50. Personally I would take cooking to 70 first so you can also start farming yellow scrips and it is the most independent crafter when it comes to cross materials.

Also if you don't have gathering classes then you should do that too.