Inscription update for the day: it’s mostly still not implemented, so still no guide from me.
To be more accurate: a lot of recipes are now available from the trainer, from skill level 1 up to 400 at present. However, the materials for the recipes have not yet been tuned. Every glyph currently requires Moonglow Ink (made from Peacebloom, Silverleaf, Earthroot, or Mageroyal), one of each type of parchment (bought from Vendors), and one piece of Mageroyal. Obviously, 400-skill recipes aren’t going to require a level 10 herb, so clearly they’re placeholders until the correct list of mats is implemented. So, there’s no point in creating a powerlevelling guide just yet.
Update: Druid glyphs appear to have the correct mats requirements. However, it’s clear that Inscription is still very unfinished, and any powerlevelling guide would be premature and inaccurate.
Also, note that the Glyphs pane of the spellbook now has three slots for Major Glyphs and three for Minor Glyphs; it looks like the model of two Major, two Minor and two Lesser has been abandoned.