Start writing novels on your computer. Write fiction novels as they take the least amount of time. They will not bring you too much Simoleons. When you write, your skill will automatically advance. If your skill is high enough you will be able to write more novel types/genres. The most money can be made from "Romance Novels". You will get royalties for six weeks once you finish a book. With the "Writing" skill maxed out, you can make about 40,000 Simoleons every week, which is more than the 34,800 Simoleons you can get by purchasing all neighborhood businesses, and takes less time to achieve. In three game weeks you should have a very high speed writing, 9 or 10 novels as best sellers and 100,000 Simoleons.