Thanks for that guide. I searched, but couldn't find it. It will help. I spent the money on the pants, the wine, and a pair of pants and a shirt for the job. (Thought they would help instead of going in the MC's underwear). And restoring the HP after failing the mission 4 times.
If you ever find yourself getting stuck in a contract, following would be my advice:
1) whichone's walkthrough for contracts that someone else already linked to you already
2) some of the early girls (i.e. Luna, Gracie, Isabel) freeroam/lewd events give you a permanent (yup, you heard it right. permanent) +1 boost in MC's stats
3) you can do Wilfred's contracts in any order. For example, if you get stuck failing Nimble Fingers, give other contracts like The Snooping Bonans and The Delivery Boy a try. You may find them much easier (in terms of stats checks at least) and easier to finish (though not 100% complete, there are different ways to finish the contract; finish but not 100%, or finish & 100% complete. 100% complete obviously offers better reward, but even so, just finish but not 100% still rewards the player to some extent).
Once you have a contract/s you were able to complete, keep on grinding them until you get decent amount of money (if you're short on money that is).
Use the money to buy better equipment which will help you for any contract you're getting stuck in.
4) Nimble Fingers contract, iirc has a very useful gear (one of the best, currently) called Lock Glasses,
given to you by an old man. Make sure to get it & equip it.
5) Just remember, with these contracts, you're not supposed to 100% complete them on your first try (something which a lot of folks tend to make a mistake of trying to do).
They're supposed to be a challenge initially, and through repetition (with contracts you've finished but not 100%), permanent stats increase (girls' events), buying equipment, and knowing when to swap in and out gear (obviously in favor for better ones) are meant to become easier.
Just have patience and stick with it, then you'll get it soon enough.
Hopefully these little hints are helpful to ya.