1. Writing. Dont make it overly serious. Dont overuse Video game jokes. Use memes extremley rarely or never at all.
2. Content. It doesnt need to have Handsome men characters. Anything can be considered a handsome men flash.
3. Voice acting. Do this
4. Artwork. Try your best. Dont restort to sticks. If your other elements are good, the graphics wont be that important.
5. Anime "Cute Flashes". NEVER, EVER, EVER, DO THIS. You can make an anime flash, as long as its good. Like Project DCK would be acceptable, but this http://www.newgrounds.com/portal/view/377449 would be fucking ban worthy.