•One of the tricks is taking some Faerie affinity that's applicable and raise it, substituting your Finesse specialty with your Affinity score.
•Flawless Magic is awesome in general, and getting to Mastery 5 (the Finesse Mastery x5) on your favorite Rego spell is only 35 xp away.
•Having a Verditius create an Item of Quality for you that's relevant also adds that item's Shape/Material bonus to the Finesse roll (per Magi of Hermes).
•Having an initial Excellent quality relevant item would add its bonus as well. (combine with Item of Quality). In fact, be a tool maker, and create Excellent/Item of Quality tool-making tools. Get some Master craftsmen grogs, prop up their shop, and invoice them an Excellent item/year, or something.
•Learned Magicians can cast Virtues on you (Way of the(), Puissant with(), Careful with(), Sanguine Humor's Blessing (if you have the appropriate Flaw), Major Essential Virtue, etc). So can Gruagach. So can Rune Magicians, but I doubt any vitkar will let a rune near a Hermetic, ever, if he has even the least notion of what Hermetic magic is like.
*Mythic Alchemists can lower the TN of making great items. Also, some materials do? Not sure about that last one.
•Arts and Academe have ligatures, a bonus of +1 to +3.
•There's a Magic Power, Grant Puissance in (ability), get a Familiar that has it for Finesse, or ally yourself with a creature that can grant it regularly in exchange for some considerations. This one can provide huge bonuses, +3/Might point spent on it
•Finally, some simply go for the spam route: rolling, rolling, rolling, until your dice explode. I dislike these spamming methods myself, in general (except for Multicast mastery ).
Combine most or all of these and you will have your troupe trying to impose limits on item bonuses, rather than struggle to meet the TN. Finesse 5 +2 Puissant + 4 Faerie Affinity + 3 Int + 4 tool (Excellent +2/Item of Quality +2) + 5 Mastery + 2 Ligature + 3 Ways of the (Land) Learned Magician indentured servant + 3 (lower TN from Mythic Alchemy) = 31
Now all of these aren't necessarily going to be approved by your Troupe, or you might not want to invest in some of these Virtues, but say you get a Learned Magician "pal", who is a Mythic Alchemist...bam! You are in business.