Had a peak at the guide, and it's no wonder you aren't getting anywhere. I can't see how you could solve the combat situations with this spell progression efficiently and without fuss, because the order is wrong. That doesn't mean it's impossible, of course, only that it is too tricky for me.
Here's a spell progression that works. Once you get the hang of the fighting style it lets you solo the fighting parts of the origin in under 20 minutes, the Wilds in about 30 minutes. Ishal separates the wheat from the chaff here. An elf with DLC items has sufficient juice to solo it in under half an hour, a human without DLC will need lyrium or more time. Soloing the ogre can take a quite while until you get the hang of that particular sport (like how to turn a Ram into an opportunity for Paralysis Explosion, reliably), so I'd recommend teamwork for that.
L01: Flame Blast, Mind Blast // creation
L02: (Flaming Weapons) // Fade
L03: Fireball // spider caves
L04: Walking Bomb // Ostagar
L05: Glyph of Paralysis // Wilds or Ostagar
---: (Glyph of Warding) // Joining
L06: Glyph of Repulsion // Ishal (ground floor)
Mind Blast is key if you go the Flame Blast route, especially as countermeasure for things like Shield Pummel or Ram. If you see the ability telegraphed then you have just barely enough time to hit the hotkey for Mind Blast. The spell also lets you put some distance between you and a ticking bomb, or some critters that are breathing down your neck, so that you can Flame Blast them in peace. It is also useful in shaping a sparse crowd into a compact, fireballable cluster.
P.S.: at this stage, the glyphs are the most powerful addition for a caster, especially when soloing. Of the spells mentioned in the guide, Force Field and Vulnerability Hex have some utility for a caster mage (including the squishy phase of an AW) but they are much more situational than the glyphs. Heal is only useful for a no-pots run and in Redcliffe; Rock Armour is presumably useful for an AW later.