Either play on Long, or turn aging off. You're going to have to grind your Sims' musical skills. Make them proficient in violin, guitar and piano. If you can, add the Digi-Organ (Portable piano thingie) to their skill. When your Sim has the required 9+ skill level on each instrument, write a song in each of the categories. Click on write song and then choose one from the menu. The piano and the organ each have six musical types, which are the same but sound different. You get six, for each instrument. The guitar and violin have five categories each. This will give you a total of twenty-one songs. Just write songs, don't bother with lyrics, they won't be recognized by the Starlight Academy. (Which grieves me to no end.) Don't license them right away. Wait until your Sim has some celebrity points under their belt. Then license one at a time. When you get the pop-up telling you the latest song you licensed received a nomination. Go to the Starlight Accolades the very next Sunday. Best of luck.
