To quickly get friends for the Cherisma skill, just play a guitar in a frequently used public place. Then all you need to do is either converse reguarly (Charisma or good sense of humour help here) or read the chrisma books in library with the Chinese incense burner (bookworm helps) to super max you definately need the humour thing.
I hate inventing, catching fire happens far too often, so much so that I put my bench right next to a bathroom.
Athletics, just go to stadium to get level one then have the sim jog everywhere, especially when collecting and when returning home from work. The gym or acadamy are the best places to do strenght workouts. I don't know if this is my imagination, but, I think that the Chinese insence burner helps here too. I always use "don't break sweat".
Bookworm is useful to quickly max logic, reading gets there much quicker if you read the books in the library, again, with the incense if you hsve it available.
In sculpting I get annoyed by the disintegrating stone, I've had three stones disintegrate on me in succession more than once. I usually pay for a mid-life crisis to get "savay sculpter" before doing this skill. And I've had two deaths while doing metal sculpters. One moment happily chisling away the next the grim reaper has arrived, no warning fire or even sparks.
Mining is a good, but dirty and rather tedious way, to get the meteors for the collecting challenge. I've never found them all on the map.
Overall, I would say inventing is the skill I find most troublesome.
But, for supermax, definately guitar. I've never completed that one. Has anyone? Those ten ops seem totally unralistic to me in a normal lifespan.