What i'm doing wrong

[Caimie_Tsukino]

and where can i get a set at level 60?

Idlehsire (scrips) or the marketboard

Vidu was referring to the "Adept crafting set":
https://ffxiv.gamerescape.com/wiki/Adept%27s_Set

You can purchase it with yellow scrips. Earn scrips it by turning-in collectables at the Appraiser NPC. To make collectable items, make sure you click the "collectable" button before you make the items.

If you have been leveling all your classes together, you should just make your own gear sets... That's probably the easiest thing to do.
If you can't make the level 61 set, make the level 51 set first to upgrade yourself in terms of stats.
And if you can't make the level 51 set, make the level 45-48 set first.

In terms of rotation, you should start learning "phases" and "combos" in a rotation. Study the tool tips of each button more closely to understand your arsenal better. Then develop your own ways of combining the actions.