Ok, well.. For the line trick thing, I don't know what to tell you. experiment. see what works. It's very easy to make it look bad but once you've made a solid loop of lines dashing by the screen and it doesn't look half bad, you're in the clear. Making your backgrounds more alive, well... Make sure to have a few layers. The last thing you want is everything stuck on the same layer. Just have movieclips of people or animals moving. It's not that hard. Also, a lot of flash artists blur their backgrounds a little for a far away look. This can be done by clicking your symbol, opening up the bottom box and choosing filters > blur. Don't let the blurring power go to your head though or before you know it, your flash looks like it could've been made by your 5 year old son in art class. good luck!