1. best time to get rid of a stock is when you feel you are happy with the amount of profit you've made. stocks can be very unpredictable as to when they will "flip", that is, going from up to down or vice versa. you may miss out on a little profit by getting out early, but better to have some profit than none :) also if you are playing close attention, you can make money both ways, hold the stock long while it is going up, then when it goes down, sell and then go short (you can make money shorting a stock that goes down, just like making money buying a stock that goes up)
2. stocks can be traded anytime morning, day. or night. When it comes to new films, those that go wide, 650 theaters or more, halt on friday at 10am Pacific and cant be traded until sunday afternoon when they adjust based on the weekend box office. then they can be traded for 3 more weeks before they delist. limited films dont adjust, once they go to the theaters, they can be traded anytime for a total of 12 weeks.
3. its almost impossible to go out of money. there is the free money for the survey, plus there is always news on the movies board that will make stocks go up or down. if you really mess up, you can reset your port back to $2M.
4. follow the boards often as you can, always good advice. and if you twitter, follow HSXMOVIES (an offical hsx twitter) and thehsxdude and HSXTips (both are veteran players who share news)
5. feel free to ask away. there are no stupid questions, only stupid people who wont ask for help! ;)