Step 1: Take one strange alien creature from outer space (a bit of hokey science is always a good one to please/outrage the nerds, depending on their pedantry value)
Step 2: Mix in a bit of good vs. evil (good wins, naturally, because that's how it happens in real life. Honestly.)
Step 3: Throw in a love interest to pull in the chicks ('cos sentimentally-minded women are really going to want to watch a schlock monster film, of course)
