I've got comberries falling out of my ears, but the rest of the possible ingredients are rare as hell. What's a good way to make these potions?

Would it be better to use Mark > X Intervention > Recall?

At higher levels you will be able to see loads of creatures that have Restore Magicka ingredients, namely Daedra Hearts and Void Salts. You will eventually collect more of these than Comberries.

You might consider one of the Magicka Restoration mods.

Mark/Recall I find useful so often that I prefer the spell. If your current character hasn't got the stuff to learn and cast it, consider trainers. Alchemy can be very lucrative over time, so you should be able to manage this.