Hey there, I'm level 50 in three crafts myself, but a long way from doing 3 star recipes yet. However, on the leveling up process i found a few things useful:

1. The level 15 skills. Especially Culinary and Alchemy. These are Hasty Touch and Tricks of the Trade. Hasty touch gives you a 50% chance to increase quality, and costs no cp. ToTT allows you to turn a "good" condition into 20cp.

If you choose not to go through every craft to 15, i'd say at least go for those two, they make a world of difference. Combining Hasty Touch with Standard Synthesis raises the increase chance to 70, and culinary level 37 Steady Hand II raises that even further to 80%.