Make sure that everybody is aware of what, for magi characters, Finesse, Concentration, Penetration, Leadership, and Magic Theory are used for. You can have perfectly viable magi characters without high scores in these --- but if you want to do lots of what these Abilities do it is frustrating to accidentally have low Scores in the relevant Abilities.
If you are using the Group combat rules (and I recommend that you do) make sure that you have some "officer" grogs (or companions, or even magi) with good Leadership Scores for leading trained groups. And be aware that trained Groups are lethal.
Remember that if you want a grog who is a tracker, then the Ability he wants is Hunt.
Be cautious, with magi characters, that you don't saddle them with lots of Academic and Arcane Abilities and Lores and Languages that seem cool, but then don't see much use in play.
One trick that I quite like to do, is to leave some Ability specialities "undefined" and then set them in play in the first few sessions (as they are needed). This way you can kind of nudge the character toward being a bit better at what he actually does in play.
Try to get the players to write down in advance (out of game time) at least half a dozen spontaneous spells that they think their magus character might want to (and can) cast. Having thought about this in advance makes it more likely that the players will think to use spontaneous magic, and speeds up doing so during game-time considerably. Even if the pre-generated spells aren't quite right for the in-game circumstances, the players will be quicker, and know roughly what the magus is capable of, if they have been through the process a few times before.
Keep a season-by-season diary for at least the magi --- it just needs to be a sentence saying what the magus did (and how many XP accrue, etc). Try to get the players to plan at least a year in advance for the magi --- acknowledging that if An Adventure Happens, then their plans may radically change. In my saga, we effectively get the magi to discuss and plan their years at the winter solstice covenant council meeting. Of course, in-character some magi are vague or lie about what they are doing, but as players we have a good idea what the magi intend to do.
When you are storyguide having a schedule like this really helps to time stories. Because of the rules that Lab season is wasted if more than about 10 days are spent away from the Lab, I try to avoid timing stories that will ruin a character's Laboratory plans. This is because you want the players to be thinking about and using the Long Term rules like the spell invention, item creation etc. So, you don't want to frustrate the players by mucking their Laboratory schedules around too much. Although, it is OK to do so occasionally, of course.