My main strategy was to pump out 3 of the instrument skills (I totally forgot to do Drums). With this, I used the guitar exploit on all of them and got 3 skill challenges easily. When my sim hit level 5 of each of them, I bought all of the compositions and learned them quickly.
I also discovered an interesting glitch - a Romantic Interest counts as a friend, no matter what the relationship level was. My sim was Charismatic, so that in combination with the "Master of Seduction" LTR meant my sim only needed to either WooHoo or Kiss a sim to make a friend. I did have to deal with the ramifications, however (accussed of cheating). My sim never really went out when I was leveling Charisma, however, so I didn't need to deal with it often. I just kept an eye on where Madeline was going and avoided her lovers. In the end, about 3 of her 13-ish lovers accused her of cheating - and I used the LTR "Clean Slate" afterwards to avoid any unpleasantness.
I didn't enjoy listening to the piano, guitar and bass over and over again, but I did enjoy the cheating part. I think that you should include a challenge like this next year. Even less for you to write in the specific challenge rules Metro - "Everything goes except Edit Town, BuyDebug and other cheats I wouldn't like you to use".
Oh, and to ease NancyJ's mind, and anyone else who wondered why Metro removed my post - I had a glitch after I discovered the glitch with Romantic Interests, where my sim could flat out not increase relationships. I fixed it by using TestingCheats to alter the relationships, always to the exact point they were. Metro believed I was flat-out cheating, but I don't think I had explained it well, so I PM'd him about it, and he let me continue.