I was reading through the tips and reached the part about having fun while gaining skills.
Writing alone is stressful, but this can be almost eliminated.
I often have my sims self employed writers, its quite easy to keep them happy and make tons of money. The sim should be a bookworm. First make sure the stereo is on and surroundings are comfortable and the sim is elated, adip in the hot tub seems to be the quickest way,. Improve art and writing simultaneously to level four. (Paint a small picture, then practice writing alternatively). At level 4 in both skills you can write children's books. These seem to cause much less stress per sim minute spent writing than other genres, but more importantly, they are very quick to complete. Have your Sim write till finished then read (one of their own children's books will do fine) then write another book. Up to four books can be written, without stress, in a single sitting this way. Ok, per book, they are worth much less than say a romance, but their shear quantity easily compensates. Obviously the challenges are much quicker to complete too. Even a child can quite happily write one children's book per day and gain a very respectable income.
Note: Books completed abroad will be paid in the usual way but will not count towards employment promotion.
Another point, not related to the writing skill, when reading skill books in the library for real speed reading take your stereo and a chinese incence burner with you. Other sims won't mind. Don't forget to pick them up again:).