What do you prioritize on in fleet shipments?

I don't really. I just buy'em as they come. I try to raise each ship to the next star level, then start working on another one. I do try to buy Slave 1 shards whenever I can though, because DS ships will be needed for the Tarkin challenge (higher tiers) and I have just one DS ship - the TIE Fighter.

This will probably change after the Vader tourney, when I won't be hoarding my AP any more. If I manage to get Vader's TIE, I'll probably save a part of my fleet tokens for Vader shards to get him to 7*.

Slave 1

Trying to get what ships I have to Max Stars, then worrying about the rest.

I'm unlocking SF and Rex so I can start gearing them, then switching over to ship materials until I can reach highest tiers of challenges, then back to SF and Rex shards

It's whatever ships u can star up the fastest to start farming zetas. After that, it's all personal choice and which Capital ship u wanna run.

Vader