Toon Leveling Help

Definitely something that's up for debate, but I feel that most people would agree that gear is at or near the top of the list. If you are short on credits or training droids (if you're a new player), then I would suggest taking them to level 50 as quick as possible and putting some mods on. Getting them to at least purple gear is a great start. I would focus on doing this for an arena team first--this will help you start the cycle of generating more crystals, and shop currency which will perpetuate getting more gear, skill abilities, etc.

Would love to talk more if you still need some help/advice. I'm on discord as The Rev#8481 (be sure to include the caps and the space) if you're interested. Best of luck!

Since you need 5 toons for a squad, ideally you're farming toons from more than one place:
-Cantina nodes
-Cantina store
-Squad Arena store
-Galactic War store
-Possibly LS/DS nodes, unless you need gear more

You can star them simultaneously without conflict in most cases. There is some overlap between gear, but usually getting to G6 is pretty easy. Same with abilities; getting them to 4 or 5 should be fast. After that, I tend to take a one-by-one approach: get a toon up to G7, ability 6, then move on to the next one until all 5 are leveled, then start over with G8 and ability 7. Of course, some abilities can be ignored; if you're never going to use a particular toon as a leader, don't waste those precious purple mats leveling up their leader ability. Mods should be assigned based on what benefits your characters; look up a mod guide to see which mods go where. If you're still pretty new, all you'll really have are health mods; focus on the primary/secondary properties and place accordingly.