making HQ items in your 20's

[Zfz]

I usually start with inner quiet and then use careful synthesis until I am i synth away from completion
Then i use Master's Mend > Steady hands and basic/hasty touch until no more Dura
Is there some better rotation for low level? (I have all the 15 cross-skills)

You should stop thinking of rotations until you're very much over-geared for the item.

Always plan ahead and synthesis when you're at low quality or have no durability room for quality.
I default to improving quality until I know I will run out of durability if I don't start with synthesis.
Also, when the remaining durability and CP tells you that you have X number of Careful Synthesis and Y number of Hasty Touch left,
then use Careful Synthesis until you hit a High Quality/one synth away from completion, then improve quality.

The key is to maximize your gain from High Quality procs. To do that, you want to have your careful synths during Normal quality.