Mine usually starts with waking up at 3 in the morning unable to get back to sleep and not needing to get back to sleep or much of it. My manic episodes also tend to build from hypomanias: being completely euphoric, exercising to an extreme degree, rapid and pressured speech. When my house is absolutely spotless, that's when I know I'm hypomanic. I just want to GO, GO, GO. I start getting these really grandiose ideas, especially to do with my writing, but sometimes I'll get an idea for some random business venture. Then things kind of fall apart from there after a bit.