Just to note, there is a lot of other Glyphs and Scroll at different skill ranges with the same amount of materials needed, so where you see [Glyph of ...] for example, there you can choose between more recipes that are orange to you and requires the same amount of materials.
First, visit any trainer in the main cities of old Azeroth - just ask a guard, and learn Inscription.
Learn Inscription Journeyman.
Make any Glyph that are orange to you and requires 1 Midnight Ink. Glyphs turns yellow after 10 points here, so then learn new recipes and choose another Glyph.
20 x [Glyph of....] - 20 Midnight Ink, 20 Light Parchment
Make any Glyph that are orange to you and requires 1 Lion's Ink. Glyphs turns yellow after 5 points, then learn new recipes and choose another Glyph.
20 x [Glyph of ...] - 20 Lion's Ink, 20 Common Parchment
Make any Glyph that is YELLOW to you, yes you read it right YELLOW. Orange recipes requires 2 Inks instead of one, so at this point it's better to make yellow recipes.
7 x [Glyph of ...] - 7 Lion's Ink, 7 Common Parchment
Learn Inscription Expert.
Turn all your [Burnt Pigment] into [Dawnstar Ink].
If you don't milled your own herbs and you don't have Burnt Pigment, you can just make any Glyph between 125-140 that are orange to you.
Orange Glyphs and Scrolls which requires 1 Jadefire Ink each.
20 x [Glyph of ...] - 20 Jadefire Ink, 20 Common Parchment
Turn all your [Indigo Pigment] into [Royal Ink] and then make as many [Arcane Tarrot] as you can. You should reach 185 or probably more.
Learn Inscription Artisan.
Orange Glyphs and Scrolls. Scrolls need 2 Parchments instead of one.
15 x [Glyph of ...] or [Scroll of...] - 15 Shimmering Ink
Now you should go and visit a trainer at Outland or Northrend, click here for the trainer list.
Usually every Glyphs turns yellow after you make 5 of them, then you will be able to learn new ones which ones are orange too. So you will have to make 4 different Glyphs for this 20 skill point.
Same as above, choose the Glyphs you want to make and are orange to you. Every orange Glyphs requires the same amount of materials at this point of the Inscription leveling guide.
Use all the rare pigment available. Keep the extra Snowfall Ink for Northrend Inscription Research. You will need to research to learn most "Northrend" glyphs.
The best strategy is stop leveling Inscription at about skill 430, and simply conduct regular Northrend Inscription Research.