Ok because im nice
Im going to give you a long list of tips.
1. Create a background, nobody likes WHITE. Its kinda gay. If you need help with creating backgrounds theres loads of tutorials on Newgrounds. Search tutorial at the top of the page.
2. Make a preloader. Sometimes if theres a big file and you want to show it it will screw up without preloaders. You can get one by going to the Flash Portal and clicking on NG Loaders. Its in the middle-top of the page.
3. Make voices? Buy a microphone, get your brother/sister to do the voices with you.
4. Animate them! :D Animate them speaking and running round, once again theres tutorials for all of the above on newgrounds.
6. Draw them yourself. Please, oh please NO SPRITES. They suck.
Hopefully you will read what advice i have given you, and use it.